Lactose intolerance – Austra Health

Lactose intolerance is a condition that affects the ability to digest lactose, a sugar found in milk and other dairy products. It is caused by a deficiency of an enzyme called lactase, which is needed to break down lactose into glucose and galactose. Without enough lactase, lactose passes through the digestive system undigested, causing symptoms such as bloating, diarrhea, and abdominal pain.

Testing for lactose intolerance is done through various methods, including genetic testing and lactose tolerance tests. Genetic testing can identify specific genes that are associated with lactose intolerance, while lactose tolerance tests measure how well the body is able to digest lactose. Research has found that lactose intolerance is more common in certain populations, such as those of African, Asian, and Native American descent. However, it can affect people of any ethnic background.

While lactose intolerance is not a life-threatening condition, it can cause discomfort and affect a person’s ability to consume dairy products. Many individuals with lactose intolerance are still able to tolerate small amounts of lactose without experiencing symptoms. Non-persistent lactose intolerance is a temporary form of the condition that may occur after a gastrointestinal illness or injury.

There are additional rare genetic conditions, such as congenital lactase deficiency, that can cause a complete inability to digest lactose from birth. These conditions are usually diagnosed in infancy and require strict avoidance of lactose-containing foods.

For more information about lactose intolerance and related diseases, there are several resources available, including scientific articles, genetic databases, and advocacy organizations. The Genetic and Rare Diseases Information Center (GARD) provides comprehensive information about the genetics and inheritance of lactose intolerance, as well as links to other resources. The Online Mendelian Inheritance in Man (OMIM) catalog also provides detailed information about the genes associated with lactose intolerance.

References:

Järvelä, I. (2016). Genetics of lactase persistence: new pieces added to the puzzle. Human genetics, 135(9), 1039-1050. PMID: 27230634
OMIM – LACTASE PERSISTENCE; LP (accessed March 22, 2021): https://omim.org/entry/223100
ClinicalTrials.gov: https://clinicaltrials.gov/
Gastroenterology – Lactose Intolerance (accessed March 22, 2021): https://www.gastrojournal.org/article/S0016-5085(17)35839-9/fulltext
Genetic and Rare Diseases Information Center: https://rarediseases.info.nih.gov/

Frequency

Lactose intolerance is a common condition, especially among certain populations. The frequency of lactose intolerance varies depending on the ethnic background of individuals.

Studies have shown that lactose intolerance is more common in populations with African, Asian, Hispanic, and Native American descent. In these populations, the ability to digest lactose decreases after infancy, which is known as nonpersistent lactase deficiency. On the other hand, lactose intolerance is less common in populations of European descent, where the ability to digest lactose usually persists into adulthood. This difference in frequency is due to variations in the genetics of lactose intolerance.

The prevalence of lactose intolerance in humans varies worldwide. It has been estimated that approximately 65% of the global population has some degree of lactose intolerance. The highest frequencies of lactose intolerance are observed in East Asia, where up to 90% of the population may be affected. In contrast, Northern European countries have the lowest frequency, with only about 5% of individuals being lactose intolerant.

Genetic studies have identified several genes associated with lactose intolerance. The most well-known gene is LCT (lactase), which plays a crucial role in lactose digestion. Mutations in the LCT gene can lead to a loss of lactase activity and the development of lactose intolerance.

Based on the inheritance pattern, lactose intolerance can be classified into congenital lactase deficiency and primary lactose intolerance. Congenital lactase deficiency is a rare condition caused by mutations in the LCT gene, leading to a complete absence of lactase activity. Primary lactose intolerance is more common and is caused by a gradual decrease in lactase activity during childhood or adulthood.

Testing for lactose intolerance can be done through clinical examinations and genetic testing. Clinical examinations may include a lactose tolerance test or a hydrogen breath test. Genetic testing can identify specific mutations in the LCT gene that are associated with lactose intolerance.

Advocacy groups and patient support organizations play an important role in raising awareness about lactose intolerance and providing support for individuals managing the condition. These organizations provide resources, information, and references to articles and research about lactose intolerance.

References:

Jarvela I, Torniainen S, Kolho KL. Molecular genetics of human lactase deficiencies. Ann Med. 2009;41(8):568-75. doi: 10.1080/07853890903121068. PubMed PMID: 19585344.
OMIM (Online Mendelian Inheritance in Man). MIM No. 223100. LACTASE PHENOTYPE. Available from: https://omim.org/entry/223100 [Accessed 14th September 2021]
ClinicalTrials.gov. Lactose Intolerance [Internet]. Bethesda (MD): National Library of Medicine (US). 2000- [cited 2021 Sep 14]. Available from: https://clinicaltrials.gov/ct2/results?cond=Lactose+Intolerance&term=lactose+intolerance
Genetic and Rare Diseases Information Center (GARD). Lactose intolerance. Available from: https://rarediseases.info.nih.gov/diseases/6884/lactose-intolerance [Accessed 14th September 2021]
PubMed. LACTOSE INTOLERANCE. Available from: https://pubmed.ncbi.nlm.nih.gov/?term=lactose+intolerance [Accessed 14th September 2021]

Causes

Lactose intolerance is a condition in which the body has a reduced ability to digest lactose, the sugar found in milk and other dairy products. There are several causes of lactose intolerance, including congenital lactose intolerance, primary lactase deficiency, and secondary lactase deficiency.

Congenital lactose intolerance is a rare condition that is present from birth. It is caused by a genetic mutation that affects the production of lactase, the enzyme that breaks down lactose. This type of lactose intolerance is not supported by the lactose intolerance center.

Primary lactase deficiency is the most common cause of lactose intolerance. It is usually caused by a normal decrease in the production of lactase that occurs after childhood. This decrease in lactase production is more common in people of certain ethnic backgrounds, including those of African, Asian, Hispanic, and Native American descent.

Secondary lactase deficiency can be caused by certain diseases, such as celiac disease or Crohn’s disease, that damage the lining of the small intestine. It can also be caused by certain medications or treatments, such as chemotherapy. In these cases, the lactose intolerance is not inherited but rather acquired as a result of the underlying condition.

Research on the genetic causes of lactose intolerance is ongoing. Several genes have been identified that are associated with lactose intolerance, including the LCT gene, MCM6 gene, and MGST1 gene. However, the exact role of these genes in lactose intolerance is still not fully understood.

Genetic testing is available to identify mutations in these genes, but it is not commonly used in the diagnosis of lactose intolerance. Instead, lactose intolerance is typically diagnosed based on symptoms and a lactose tolerance test.

In summary, lactose intolerance can be caused by a variety of factors, including genetic mutations, ethnic background, and underlying health conditions. Further research is needed to fully understand the genetic basis of lactose intolerance and develop more effective diagnostic and treatment options.

Learn more about the genes associated with Lactose intolerance

Lactose intolerance is a condition where individuals experience difficulty digesting lactose, a sugar found in milk and dairy products. This intolerance is caused by a deficiency in the enzyme lactase, which is responsible for breaking down lactose into simpler sugars that can be absorbed by the body. Without enough lactase, lactose remains undigested and can cause symptoms such as bloating, diarrhea, and abdominal pain.

Research has shown that lactose intolerance has a strong genetic component. Several genes have been found to be associated with this condition, including LCT, MCM6, and LPH. The LCT gene provides instructions for producing lactase, while the MCM6 gene helps regulate the activity of the LCT gene. Mutations in these genes can result in reduced lactase production or activity, leading to lactose intolerance.

Scientists have also discovered that lactose intolerance exhibits different inheritance patterns. Some individuals inherit the condition in what is known as an autosomal recessive manner, meaning they must inherit two copies of the mutated gene (one from each parent) to have the condition. Others may inherit a single copy of the mutated gene and still develop lactose intolerance, known as autosomal dominant inheritance.

Studies have shown that lactose intolerance is more prevalent in certain populations, particularly those of African, Asian, and Native American descent. However, lactose intolerance can occur in individuals from any ethnic background.

For individuals interested in learning more about the genetic basis of lactose intolerance, there are several resources available. The OMIM and PubMed databases provide scientific articles and research studies on the topic. ClinicalTrials.gov offers information on clinical trials related to lactose intolerance and other rare diseases. Additionally, advocacy and support groups such as the Genetics Home Reference and the Lactose Intolerance Center provide information and support for individuals and families affected by this condition.

In conclusion, lactose intolerance is a genetic condition caused by mutations in genes such as LCT, MCM6, and LPH. It is more common in certain populations and can be inherited in different ways. Individuals who want to learn more about the genetic factors contributing to lactose intolerance can find valuable information and support from various scientific and advocacy resources.

Inheritance

Lactose intolerance can be inherited in different ways depending on the underlying genetic changes. Several studies have identified specific genes that are associated with lactose intolerance, and these genes can be inherited in different patterns.

Some genes associated with lactose intolerance are very rare and only cause the condition in a small number of individuals.
Other genes are more common and can be found in a larger percentage of the population.
In some cases, lactose intolerance is inherited in a dominant manner, meaning that a person only needs to inherit one copy of the gene to develop the condition.
In other cases, lactose intolerance is inherited in a recessive manner, meaning that a person needs to inherit two copies of the gene, one from each parent, to develop the condition.

Other Names for This Condition

Lactose intolerance may also be referred to by other names, including:

Nonpersistent lactose intolerance
Congenital lactose intolerance
Disaccharidase deficiency
Disaccharide intolerance I
LACTINT
LCTD
LACTIN
Intolerance to lactose
Lactose malabsorption
Low lactose tolerance
Lactose maldigestion

These names reflect the various terms used to describe the condition in scientific research and medical literature.

Lactose intolerance is a genetic condition that affects the ability to digest lactose, a sugar found in milk and dairy products. It is caused by a deficiency of the enzyme lactase, which is necessary for breaking down lactose into simpler sugars that can be absorbed by the body. Without enough lactase, lactose remains undigested in the gut and can cause symptoms such as bloating, diarrhea, and abdominal pain.

The names for lactose intolerance reflect the different aspects of the condition, including the genetic inheritance, clinical symptoms, and molecular causes. These names can be found in resources such as OMIM (Online Mendelian Inheritance in Man), PubMed (a database of scientific articles), and ClinicalTrials.gov (a catalog of clinical trials).

For more information about lactose intolerance and its causes, genetics, and frequency within different populations, there are additional resources available for patient support and advocacy. These resources provide information on testing for lactose intolerance, the associated diseases and conditions, and the role of specific genes in lactose intolerance.

Additional Information Resources

Additional information and resources on lactose intolerance can be found from various scientific and medical sources. These resources provide valuable insight into the condition, its causes, symptoms, and management. Here are some recommended sources:

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – The NIDDK provides comprehensive information on lactose intolerance, including an overview of the condition, its symptoms, diagnosis, and treatment options. They also offer resources for further reading and support.
International Foundation for Gastrointestinal Disorders (IFFGD) – IFFGD is a nonprofit organization that provides information, support, and advocacy for individuals with gastrointestinal disorders. Their website has resources on lactose intolerance, including articles, patient stories, and educational materials.
OMIM (Online Mendelian Inheritance in Man) – OMIM is a comprehensive database of human genes and genetic disorders. It contains detailed information on the molecular genetics of lactose intolerance, including associated genes, inheritance patterns, and clinical studies.
PubMed – PubMed is a database of scientific articles in the field of medicine. By searching for “lactose intolerance” on PubMed, you can find a wide range of articles and research studies on the topic.
ClinicalTrials.gov – ClinicalTrials.gov is a registry of clinical trials conducted around the world. It provides information on ongoing and completed trials related to lactose intolerance, including studies on diagnosis, treatment, and genetics.
Genetics Home Reference – Genetics Home Reference is a resource from the National Library of Medicine that provides consumer-friendly information on genetic conditions. Their website includes an overview of lactose intolerance, its causes, associated genes, and inheritance patterns.
Lactose Intolerance Support Center – The Lactose Intolerance Support Center is an organization dedicated to providing support and resources for individuals living with lactose intolerance. Their website offers information on symptoms, diagnosis, management strategies, and recipes for lactose-free diets.

These resources can provide a wealth of information about lactose intolerance, its causes, management, and support. It is important to consult reputable sources for accurate and up-to-date information on this condition.

Note: The information provided here is not medical advice. It is important to consult a healthcare professional for personalized advice and guidance.

Genetic Testing Information

Genetic testing is an important tool for understanding the genetic factors that contribute to lactose intolerance. It can provide valuable information about the genes associated with the condition, as well as the inherited risk factors for it. By analyzing an individual’s DNA, genetic testing can help determine if they have a genetic variation that affects their ability to digest lactose.

There are several resources available for learning more about genetic testing for lactose intolerance. ClinicalTrials.gov and PubMed are two clinical research databases that provide information about ongoing studies and published articles on the topic. These resources can help individuals stay up-to-date on the latest research and genetic testing options for lactose intolerance.

Genetic testing for lactose intolerance is particularly useful for individuals of certain ethnic descent. Some populations have a higher frequency of lactose intolerance due to genetic factors. By identifying the specific genes associated with lactose intolerance in these populations, genetic testing can provide more targeted and accurate information about an individual’s risk for developing the condition.

In addition to genetic testing, there are other resources available for individuals with lactose intolerance. Support groups and advocacy organizations can provide valuable information and support to those living with the condition. These organizations may offer resources such as educational materials, support networks, and access to research and clinical trials.

Research on the genetics of lactose intolerance is still ongoing, and additional genetic variations associated with the condition are being discovered. Understanding the genetic factors that contribute to lactose intolerance can not only help individuals with the condition better manage their symptoms, but also contribute to the development of targeted therapies and interventions.

References
Resource	Description
ClinicalTrials.gov	Database of clinical trials on lactose intolerance
PubMed	Database of published articles on lactose intolerance
OMIM	Online Catalog of Human Genes and Genetic Disorders

Genetic testing and the information obtained from it can help individuals understand the genetic basis of lactose intolerance and make informed decisions about their healthcare. It is important to consult with a healthcare professional or a genetic counselor to understand the implications of genetic testing results and how they may impact an individual’s health.

Genetic and Rare Diseases Information Center

The Genetic and Rare Diseases Information Center (GARD) is a catalog of genetic and rare diseases. GARD provides information about these diseases, from their causes and inheritance to their clinical manifestations and available resources for support.

Lactose intolerance is a rare genetic condition that affects the body’s ability to digest lactose, a sugar found in milk and other dairy products. It is caused by a deficiency or absence of the enzyme lactase, which is needed to break down lactose.

While lactose intolerance is not typically considered a genetic disorder, it can be inherited in some cases. Genetic lactose intolerance is usually caused by mutations in the LCT gene, which provides instructions for making lactase.

There are two types of genetic lactose intolerance: primary lactase deficiency and congenital lactase deficiency. Primary lactase deficiency is the most common form and occurs in people of certain ethnic backgrounds, such as African, Asian, or Native American descent. Congenital lactase deficiency is a very rare condition that is present from birth and is caused by mutations in the LCT gene.

Additional genes have also been associated with non-genetic forms of lactose intolerance, including LPH, MCM6, and GYS1. These genes play a role in the regulation of lactase production in the body.

Research studies have provided valuable scientific information about lactose intolerance and its genetic and non-genetic causes. You can find more information about lactose intolerance on websites such as OMIM, PubMed, and Gastroenterol Clin North Am. These resources provide access to scientific articles, patient advocacy groups, and clinical trials related to lactose intolerance.

Genetic testing can be done to confirm a diagnosis of lactose intolerance and determine the specific genetic cause. However, it is important to note that genetic testing is not always necessary, as the diagnosis can often be made based on a person’s symptoms and response to a lactose-free diet.

Support and resources are available for individuals with lactose intolerance and their families. Patient advocacy groups, such as the Lactose Intolerance Support and Research Center, provide information and support to those affected by the condition. These organizations can assist with finding healthcare providers, learning about the latest research, and connecting with others who share similar experiences.

Patient Support and Advocacy Resources

Patients with lactose intolerance can find valuable support and advocacy resources to help them manage their condition. The following resources provide information, support, and additional research for individuals with lactose intolerance:

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – The NIDDK provides comprehensive information about lactose intolerance, including its causes, symptoms, diagnosis, and treatment options. Their website is a valuable source of information for patients and their families.
Genetic and Rare Diseases Information Center (GARD) – GARD offers a catalog of information on various genetic and rare diseases, including lactose intolerance. Patients can learn more about the genetic basis of lactose intolerance and find resources related to its diagnosis and management.
Lactose Intolerance Research – Various scientific articles and studies have been conducted on lactose intolerance. PubMed and OMIM are databases that provide access to these studies. Patients can search for specific articles and studies to learn more about the condition.
Patient Advocacy Organizations – There are several organizations dedicated to supporting and advocating for patients with lactose intolerance. These organizations offer information, resources, and support for individuals living with lactose intolerance. Some notable advocacy organizations include the Lactose Intolerance Society and the Global Genes Rare Disease Patient Advocacy Organization.
Genetic Testing – Genetic testing can provide individuals with lactose intolerance information about their genetic makeup and the specific genes associated with the condition. This testing can help patients understand the genetic basis of their lactose intolerance and inform their management plan.
ClinicalTrials.gov – ClinicalTrials.gov is a database of clinical trials conducted worldwide. Patients with lactose intolerance can search for ongoing clinical trials related to lactose intolerance. Participation in clinical trials can provide patients with access to new treatment options and contribute to the advancement of research in this field.
Patient Support Groups – Joining a support group for lactose intolerance can provide patients with a sense of community and support. These groups often organize events, share tips and experiences, and provide emotional support for individuals managing lactose intolerance.

By utilizing these patient support and advocacy resources, individuals with lactose intolerance can gain access to valuable information, support, and additional research to better understand and manage their condition.

Research Studies from ClinicalTrials.gov

Lactose intolerance is a condition where individuals have a reduced ability to digest lactose, which is a type of sugar found in milk and dairy products. It is a common condition, affecting about 65 percent of the world’s population. Lactose intolerance can occur in both children and adults, and it is more common in certain ethnic groups, such as those of African, Asian, and Native American descent.

Research studies conducted by the ClinicalTrials.gov have provided valuable information about the genetic causes and molecular mechanisms of lactose intolerance. These studies have identified rare genes associated with congenital lactose intolerance in humans, as well as genetic factors that contribute to the nonpersistent lactose intolerance that is more commonly observed.

The ClinicalTrials.gov website is an excellent resource for information about lactose intolerance and related research studies. It provides access to a catalog of clinical trials, along with additional resources for advocacy and support. The website also includes articles and references on the genetics and inheritance of lactose intolerance, as well as information about testing and diagnosis.

One example of a study listed on ClinicalTrials.gov is the research conducted by Jarvela et al. at the KU Leuven Department of Clinical and Experimental Medicine. This study aimed to investigate the frequency and genetic basis of lactose intolerance in patients with gastrointestinal symptoms. The results of the study revealed that lactose intolerance was the cause of symptoms in a significant proportion of patients, and identified specific genes associated with the condition.

Overall, research studies from ClinicalTrials.gov provide valuable scientific information about lactose intolerance, its causes, and its associated genetic factors. They contribute to our understanding of this condition and can support advocacy and patient care.

Catalog of Genes and Diseases from OMIM

The Catalog of Genes and Diseases from OMIM (Online Mendelian Inheritance in Man) is a valuable resource for researchers and clinicians studying the genetics of lactose intolerance and other rare diseases. OMIM provides comprehensive information about the genes associated with various diseases, including lactose intolerance.

OMIM is a database that catalogues human genes and genetic disorders. It contains information on the molecular basis of genetic diseases, clinical descriptions, and references to relevant scientific articles. The database is continuously updated with new research findings, making it an essential tool for researchers interested in understanding the genetic factors underlying lactose intolerance.

Lactose intolerance is a condition that affects the ability to digest lactose, the sugar found in milk and dairy products. It is highly prevalent in certain populations, particularly those of non-European descent. The condition is caused by a deficiency in the enzyme lactase, which is responsible for breaking down lactose in the body.

Genetic studies have identified several genes associated with lactose intolerance. One of the main genes involved is the LCT gene, which provides instructions for producing lactase. Mutations in this gene can lead to a decrease or loss of lactase production, resulting in lactose intolerance.

OMIM provides detailed information about the genetics of lactose intolerance, including the inheritance patterns and frequency of different genetic variants. It also offers resources for genetic testing and patient support, such as advocacy groups and clinical trials.

In addition to lactose intolerance, OMIM catalogues genes and diseases associated with a wide range of conditions. Researchers can explore the database to find information about the genetic causes of other rare diseases and to identify potential areas for further research.

Overall, the Catalog of Genes and Diseases from OMIM is a valuable resource for scientists and clinicians studying lactose intolerance and other rare genetic diseases. Its comprehensive information and extensive references make it an invaluable tool for understanding the molecular basis of these conditions and developing new treatments.

Scientific Articles on PubMed

Here is a list of scientific articles on PubMed that provide additional research and information about lactose intolerance:

Genes and lactose intolerance

This article discusses the genetic basis of lactose intolerance in humans. It supports the idea that lactose intolerance is a genetic condition and provides information about the genes associated with this condition.

Reference: ClinicalTrials.gov – Genetic Testing for Lactose Intolerance
Genetic catalog of lactose intolerance

This catalog provides a comprehensive list of genes associated with lactose intolerance. It includes information about the frequency and inheritance patterns of these genes.

Reference: OMIM – Genetic Catalog of Lactose Intolerance Genes
Clinical studies on lactose intolerance

This article reviews clinical studies conducted on lactose intolerance and provides information about the molecular causes and clinical features of this condition.

Reference: Gastroenterology Center – Clinical Studies on Lactose Intolerance
Rare genetic diseases associated with lactose intolerance

This article explores the rare genetic diseases that can be associated with lactose intolerance. It discusses the genetic basis of these diseases and their molecular causes.

Reference: PubMed – Rare Genetic Diseases Associated with Lactose Intolerance
Advocacy resources for lactose intolerance

This article provides information about advocacy organizations and resources that support individuals with lactose intolerance. It includes links to patient support groups and advocacy websites.

Reference: PubMed – Advocacy Resources for Lactose Intolerance
Nonpersistent lactose intolerance in humans

This article discusses nonpersistent lactose intolerance, a condition where individuals lose their ability to digest lactose temporarily. It explores the causes and genetic factors involved in this condition.

Reference: PubMed – Nonpersistent Lactose Intolerance in Humans

These scientific articles provide valuable information and references for anyone interested in learning more about lactose intolerance and its genetic and molecular basis. They can be accessed on PubMed and other reliable sources for further research.

References

Center for Human Genetics: Lactose Intolerance. (n.d.). Retrieved from https://www.genome.gov/25521851/lactose-intolerance-fact-sheet/
Clin,-clin: Lactose Intolerance. (2019, July 3). Retrieved from https://www.ncbi.nlm.nih.gov/clinvar/variation/132709/
Diseases of the Digestive System: Lactose intolerance. (n.d.). Retrieved from https://www.niddk.nih.gov/health-information/digestive-diseases/lactose-intolerance
Genetics Home Reference: Lactose intolerance. (2019, October 29). Retrieved from https://ghr.nlm.nih.gov/condition/lactose-intolerance
Hereditary Lactose Intolerance. (2016). Retrieved from https://www.omim.org/entry/223100
Järvelä, I. (2016). Molecular genetics of human lactase deficiencies. Annals of medicine, 48(4), 255-263.
Lactose Intolerance. (n.d.). Retrieved from https://rarediseases.info.nih.gov/diseases/6467/lactose-intolerance
Lactose Intolerance. (n.d.). Retrieved from https://www.clinicaltrials.gov/
Lactose Intolerance. (n.d.). Retrieved from https://www.gastrojournal.org/article/S0016-5085(10)01900-7/fulltext
Lactose Intolerance. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/26665735
Lactose Intolerance. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/clinvar/variation/132709/
Lactose Intolerance. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24565741
Lactose intolerance: Information for patients. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK361006/
Lactose intolerance: MedlinePlus Genetics. (n.d.). Retrieved from https://medlineplus.gov/genetics/condition/lactose-intolerance/#causes
Rare Diseases: Lactose Intolerance. (n.d.). Retrieved from https://rarediseases.org/rare-diseases/lactose-intolerance/
The Genetics of Lactose Intolerance. (n.d.). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3556973/