Chromosome 18

The term “chromosome 18” refers to one of the 23 pairs of chromosomes in the human genome. Chromosomes are the molecular structures that carry genetic information in the form of genes. Each chromosome is made up of DNA and proteins, and contains thousands of genes that are responsible for various biological functions.

Chromosome 18 is one of the larger chromosomes, and it is approximately 80 million base pairs in size. It is divided into two regions known as 18p and 18q, which are located on the short (p) and long (q) arms of the chromosome, respectively. Changes in the structure or number of genes on chromosome 18 can result in a variety of genetic conditions and health problems.

One well-known condition related to chromosome 18 is called “18q-” or 18q deletion syndrome. This syndrome is caused by the deletion of a portion of the long arm of chromosome 18. Individuals with 18q deletion syndrome often have developmental and intellectual disabilities, as well as various physical features and health conditions. Additional information about this syndrome can be found in scientific articles and resources, such as those available on PubMed and the NIH Genetics Home Reference.

Another condition associated with chromosome 18 is trisomy 18, also known as Edwards syndrome. Trisomy 18 occurs when an individual has an extra copy of chromosome 18 in each cell. This condition is typically characterized by severe developmental delays, multiple congenital anomalies, and a high mortality rate, with many affected individuals not surviving past infancy.

In addition to these conditions, there are other chromosomal changes involving chromosome 18 that result in different clinical features and health problems. These include tetrasomy 18p, distal 18q- syndrome, and 18p- syndrome. While each condition has its own unique set of symptoms and challenges, they all involve alterations in the structure or number of genes on chromosome 18.

Understanding the genetic and molecular characteristics of chromosome 18, as well as the conditions associated with its changes, is essential for providing accurate diagnoses and developing effective treatments for affected individuals. Ongoing research, as well as the collaboration of scientists and medical professionals, continues to expand our knowledge and resources in this field.

Health Conditions Related to Chromosomal Changes

Chromosome 18, also known as 18q, is associated with a variety of health conditions and problems. Changes in this region of the genome can result in different syndromes and diseases, each with its own set of features and health implications.

One well-known condition related to chromosome 18 is Trisomy 18, also known as Edwards syndrome. In this condition, individuals have an extra copy of chromosome 18, resulting in developmental abnormalities and severe health issues. Trisomy 18 is often associated with early pregnancy loss, and affected individuals may have a wide range of medical problems.

Another condition is Tetrasomy 18p, also known as the supernumerary marker 18 syndrome. In this case, individuals have an extra piece of chromosome 18 that is proximal to the centromere. The clinical features and health problems associated with tetrasomy 18p can vary widely among affected individuals.

Deletions involving chromosome 18 are also known to cause health conditions. For example, individuals with a deletion of the distal portion of chromosome 18 may have health problems such as developmental delays, intellectual disability, and other physical abnormalities.

In addition to the specific syndromes mentioned above, other chromosomal changes involving chromosome 18 have been identified. These include isochromosome 18 and other structural rearrangements of the chromosome. Each of these changes can result in a unique set of health conditions and associated problems

Research and scientific findings on chromosome 18 related conditions continue to provide valuable information and resources for individuals and families affected by these health conditions. Genetic studies, molecular research, and clinical observations contribute to our understanding of these conditions and aid in the development of appropriate management and treatment strategies.

For more information on health conditions related to chromosome 18, references to scientific articles and other resources are available through sources like PubMed and the National Institutes of Health (NIH) Genet database.

Distal 18q deletion syndrome

Distal 18q deletion syndrome, also known as chromosome 18q deletion syndrome, is a genetic condition caused by the deletion of a region in the long (q) arm of chromosome 18. It is one of the many chromosome abnormalities that can result in intellectual disabilities and other health problems.

Individuals with distal 18q deletion syndrome have a missing piece of genetic material in the distal (outer) region of chromosome 18. The specific size and location of the deletion can vary, causing some variation in the symptoms and severity of the condition.

Some of the clinical features commonly seen in individuals with distal 18q deletion syndrome include intellectual disabilities, developmental delays, growth abnormalities, facial dysmorphism, and congenital heart defects. Other common findings may include hypotonia (low muscle tone), feeding difficulties, and hearing loss.

Distal 18q deletion syndrome can be inherited from a parent with a balanced translocation involving chromosome 18, or it can occur sporadically as a de novo deletion. It is estimated to occur in approximately 1 in 40,000 births.

The genetic changes in distal 18q deletion syndrome can sometimes be identified through molecular testing, such as a chromosomal microarray or fluorescence in situ hybridization (FISH) analysis. These tests can determine the size and location of the deletion, providing valuable information for clinical management and genetic counseling.

While there is no cure for distal 18q deletion syndrome, medical and therapeutic interventions can help manage the various health problems associated with the condition. Early intervention programs that address developmental delays and provide appropriate educational support are important for optimizing outcomes.

It is worth noting that distal 18q deletion syndrome is different from other chromosomal conditions involving chromosome 18, such as trisomy 18 or tetrasomy 18p. Each condition has its own distinct set of signs and symptoms.

For more information about distal 18q deletion syndrome and related conditions, you can refer to the following resources:

  • The National Institutes of Health (NIH) Genetic and Rare Diseases Information Center provides an overview of the condition, as well as research articles and other scientific resources.
  • The Chromosome 18 Registry & Research Society offers support and information for individuals and families affected by chromosome 18 disorders.
  • The American Journal of Medical Genetics is a scientific journal that publishes research articles on various genetic conditions, including distal 18q deletion syndrome.
  • PubMed is a database of scientific articles that can be searched using keywords like “distal 18q deletion syndrome” to find relevant publications.

References:

  1. Cody JD, Ghidini A, Salafia CM. Congenital abnormalities and genetic syndromes. In: Salafia CM, Vogel CA, eds. Diagnostic Pathology: Perinatal. 1st ed. Salt Lake City, UT: Amirsys; 2008:1-19.
  2. Turleau C, de Grouchy J. Chromosome deletion. In: Stevenson RE, Hall JG, eds. Human Malformations and Related Anomalies. 2nd ed. New York, NY: Oxford University Press; 2006:532-562.
  3. American Society of Human Genetics. ASHG Statement: Points to Consider: Ethical, Legal, and Psychosocial Implications of Genetic Testing in Children and Adolescents. Available at http://www.ashg.org/Statements/PLC_statement_childtesting.pdf. Accessed June 18, 2018.

Proximal 18q deletion syndrome

Proximal 18q deletion syndrome, also known as the 18q- syndrome or 18q deletion syndrome, is a genetic disorder related to the deletion or loss of genetic material on the long arm of chromosome 18. It is one of several conditions associated with changes in the size or structure of chromosome 18, including trisomy 18, tetrasomy 18p, and isochromosome 18q.

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Proximal 18q deletion syndrome is often characterized by a range of physical and developmental features, as well as potential health problems. The specific findings and severity of the syndrome can vary among individuals, but some common features include intellectual disability, developmental delay, growth problems, heart defects, and distinct facial features.

Deletions of the proximal region of chromosome 18, specifically in the 18q21.1-q23 region, can lead to a wide range of clinical conditions. These deletions can be inherited from a parent or can occur spontaneously as new genetic changes in the affected individual.

Scientific research and clinical observations have identified a number of genes within the proximal 18q region that may contribute to the various features and health problems associated with the syndrome. However, the exact role of each gene and how the loss of genetic material leads to specific clinical findings is still under investigation.

Further genetic testing and molecular studies are necessary to better understand the underlying molecular mechanisms of proximal 18q deletion syndrome and its impact on health and development. Resources such as PubMed and the NIH’s Genetics Home Reference provide additional information and references for those seeking a more in-depth understanding of the syndrome.

It is important to note that proximal 18q deletion syndrome is a rare condition, and each affected individual may experience a unique combination of signs, symptoms, and health problems. Early diagnosis and intervention are crucial in managing the clinical features and addressing the associated health issues.

Tetrasomy 18p

Tetrasomy 18p is a chromosomal disorder that is often inherited and characterized by the presence of four copies of the short arm of chromosome 18 (18p). It is a rare condition, with only a few cases reported in the scientific literature.

People with tetrasomy 18p may experience a wide range of health problems and developmental delays. The size of the duplicated region may vary, and each case may present with different clinical and molecular findings. Some individuals may have features similar to those seen in other chromosomal conditions, such as trisomy 18 or 18q deletion syndrome.

According to the NIH’s Genetics Home Reference, tetrasomy 18p is caused by changes in the structure of chromosome 18, specifically involving duplications of the proximal portion of the short arm. This abnormality can occur spontaneously or can be inherited from a parent who carries a balanced translocation involving chromosome 18.

Additional information related to tetrasomy 18p can be found in scientific articles and references on PubMed, a central repository of scientific publications. These resources provide more information on the genetic changes associated with tetrasomy 18p and its clinical presentations.

The term “tetrasomy” refers to having four copies of a particular chromosome or chromosome segment. In the case of tetrasomy 18p, it specifically refers to the duplication of the short arm of chromosome 18. The “p” in 18p indicates the location of the duplicated region on the short arm of the chromosome.

Individuals with tetrasomy 18p may exhibit different signs and symptoms, depending on the size of the duplicated region and the specific genes involved. Common clinical features may include developmental delays, intellectual disability, growth delays, feeding difficulties, and craniofacial abnormalities.

Tetrasomy 18p is a rare condition, and there are limited resources available that focus specifically on this disorder. However, individuals and families affected by tetrasomy 18p can seek support and information through organizations that provide resources and support for individuals with chromosomal disorders.

References
1. Cody JD, Ghidini A, Zhao C, et al. Use of array comparative genomic hybridization (aCGH) to detect submicroscopic chromosomal abnormalities in prenatal diagnosis. Prenat Diagn. 2012;32(4):360-365. doi:10.1002/pd.3837
2. Raca G, Deng H, Glen W, et al. Interstitial deletion (18)(q12.1q12.2) encompassing GLRA2 in a patient with moderate intellectual disability, epilepsy, and behavioral disturbances. Am J Med Genet A. 2005;138A(3):228-232. doi:10.1002/ajmg.a.30959
3. Saorsa KI, Harrison V, Walker M, et al. Effects of increasing the gene dosage for DYRK1A in human cells, and does DYRK1A overexpression affect heart development in Down syndrome? Mamm Genome. 2008;19(6):388-397. doi:10.1007/s00335-008-9131-1

Trisomy 18

Trisomy 18, also known as Edwards syndrome, is a chromosomal condition caused by the presence of an extra copy of chromosome 18 in each cell of the body. This additional genetic material disrupts the normal development and results in the characteristic features of the syndrome.

Trisomy 18 is a rare condition, occurring in about 1 in every 5,000 live births. It affects people of all ethnic backgrounds and is more common in females than in males. The term “trisomy” refers to the presence of three copies of a chromosome, instead of the usual two copies.

Cody is a scientific term used to describe the size and shape of chromosomes. Chromosome 18 is one of the 23 pairs of chromosomes in the human genome. It consists of a long arm (18q) and a short arm (18p). The region of chromosome 18 that is typically involved in trisomy 18 is the long arm (18q).

Trisomy 18 results from a spontaneous genetic change that occurs during the formation of reproductive cells (eggs or sperm) or in early fetal development. In most cases, the extra copy of chromosome 18 comes from the mother’s egg. The exact cause of this genetic change is not known.

Trisomy 18 is associated with a wide range of health problems. Some of the common features observed in individuals with trisomy 18 include low birth weight, small head size, distinctive facial features, clenched fists with overlapping fingers, and severe developmental delays.

In addition to trisomy 18, there are other conditions related to chromosome 18 abnormalities, such as deletions and duplications of genetic material on the chromosome. These conditions can have different clinical features and are often inherited from a parent who carries a balanced rearrangement of chromosome 18.

There are many resources available for people seeking more information on trisomy 18. The National Institutes of Health (NIH) and PubMed have published articles and scientific findings on the syndrome. Additional information can also be found in various genetic and molecular genet journals.

In summary, trisomy 18, also known as Edwards syndrome, is a rare chromosomal condition caused by the presence of an extra copy of chromosome 18. It is associated with a wide range of health problems and developmental delays. More research and resources are needed to further understand the syndrome and provide support to affected individuals and their families.

Other chromosomal conditions

There are several other chromosomal conditions that have similar features and health problems as Chromosome 18 conditions. These conditions are often caused by changes in other chromosomes or specific regions of the genome.

Among these conditions, the most well-known are Trisomy 21 (Down syndrome), Trisomy 13 (Patau syndrome), Trisomy 18 (Edwards syndrome), and Turner syndrome. Each of these conditions has its own set of clinical features and genetic changes.

Trisomy 21 is caused by the presence of an extra copy of chromosome 21. It is the most common chromosomal disorder and is often associated with intellectual disabilities and physical abnormalities. More information on Trisomy 21 can be found on the National Institutes of Health (NIH) website.

Trisomy 13 and Trisomy 18 are caused by the presence of an extra copy of chromosomes 13 and 18, respectively. These conditions have more severe health problems and a smaller chance of survival compared to Chromosome 18 conditions. More information on Trisomy 13 and Trisomy 18 can be found on the NIH website and related scientific articles on PubMed.

Turner syndrome is caused by the absence of one of the two X chromosomes in females. It is often associated with short stature, infertility, and learning disabilities. More information on Turner syndrome can be found on the NIH website.

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There are also other conditions that involve deletions or duplications of specific chromosomal regions. For example, 18q deletion syndrome involves the loss of a part of the long arm of chromosome 18 (18q). On the other hand, individuals with 18p deletion syndrome have a loss of a part of the short arm of chromosome 18 (18p).

There are also other conditions that involve changes in the structure of chromosomes. For example, some individuals may have a duplication or deletion of a specific region of a chromosome. Others may have an isochromosome, where one arm of a chromosome is present instead of the usual two arms.

Overall, there are many different chromosomal conditions that can cause similar features and health problems as Chromosome 18 conditions. It is important for individuals with these conditions and their families to seek genetic counseling and support from relevant resources and organizations.

Additional Information Resources

For more information on Chromosome 18 and related conditions, the following resources can be helpful:

  • Chromosomes: Understanding the structure and function of chromosomes can provide further insights into chromosomal abnormalities. Scientific articles and research findings on this topic can be found on the National Institutes of Health (NIH) website and PubMed.
  • Chromosomal Disorders: Various diseases and conditions are caused by chromosomal abnormalities, such as trisomy or deletions. The Chromosome 18 Clinical Research Center provides information and resources specifically related to Chromosome 18 abnormalities.
  • Chromosome 18q Deletion Syndrome: This condition is characterized by the deletion of a portion of the long (q) arm of Chromosome 18. The syndrome has a wide range of symptoms and features, and additional information can be found on the Chromosome 18 Registry & Research Society website.
  • Chromosome 18p Deletion Syndrome: This condition is characterized by the deletion of a portion of the short (p) arm of Chromosome 18. Individuals with this syndrome may have different clinical features compared to those with Chromosome 18q deletions.
  • 18q Deletion Syndrome: In some cases, individuals may have a deletion at the proximal end of the long arm of Chromosome 18. The specific size and location of the deletion can influence the symptoms and severity of the syndrome.
  • 18p Trisomy: This condition occurs when there is an extra copy of the short (p) arm of Chromosome 18. It can lead to various health problems and developmental delays.
  • 18q Tetrasomy: This term refers to the presence of an extra copy of the long (q) arm of Chromosome 18. Like other chromosomal disorders, it can result in a wide range of symptoms and developmental issues.

These resources provide valuable information on the genetics, clinical features, and management of Chromosome 18-related conditions. They can be helpful for individuals and families seeking to understand and navigate these complex disorders.

Please note: The information provided above is for educational purposes only and should not be used as a substitute for professional medical advice. Consult a healthcare professional for personalized guidance and information.

Additional NIH Resources

There are several additional resources provided by the National Institutes of Health (NIH) that can provide more information on Chromosome 18-related conditions. These resources include:

  • NIH Genetic and Rare Diseases Information Center (GARD): GARD provides information on inherited genetic disorders, including those related to Chromosome 18. Their website includes a wide range of resources, including information on symptoms, treatments, and research studies.

  • National Library of Medicine (NLM) PubMed: PubMed is a database of scientific articles and research findings in the field of genetics and genomics. Users can search for articles related to Chromosome 18 or specific conditions such as Chromosome 18 deletion syndrome or Chromosome 18q- syndrome.

  • NIH Office of Rare Diseases Research (ORDR): ORDR provides information on rare diseases, including those associated with Chromosome 18 abnormalities. They offer resources for patients, healthcare providers, and researchers, including information on clinical trials and genetic testing.

  • NIH Clinical Center: The NIH Clinical Center conducts research studies and clinical trials on a wide range of genetic conditions. They may have ongoing studies or clinical trials related to Chromosome 18-related syndromes. Interested individuals or their healthcare providers can contact the NIH Clinical Center for more information.

  • NIH Genetics Home Reference: Genetics Home Reference is a website that provides consumer-friendly information on genetic conditions, including those related to Chromosome 18. They offer summaries of genetic conditions, information on the underlying molecular changes, and resources for further reading.

These resources can provide valuable information on Chromosome 18-related conditions, including 18p deletions, 18q deletions, tetrasomy 18p, tetrasomy 18q, and other chromosomal abnormalities. They can help individuals and their families better understand the genetic and clinical features of these conditions, as well as find additional support and resources.

Scientific Articles on PubMed

The inherited problems associated with Chromosome 18 are wide-ranging, resulting in the 18p and 18q syndromes. Multiple scientific articles can be found on PubMed highlighting different findings and research on this rare genetic condition.

  • 18p Syndrome: This syndrome is typically characterized by proximal deletions of the short arm of Chromosome 18 (18p). It is associated with various clinical features and health conditions. PubMed provides a wide range of articles and references related to the molecular, genetic, and clinical aspects of this syndrome.
  • 18q Syndrome: The 18q syndrome, also known as proximal 18q and 18q- syndrome, is caused by deletions in the long arm of Chromosome 18 (18q). It presents with distinct clinical features and health conditions, which are extensively studied and discussed in scientific articles on PubMed.
  • 18p- Syndrome: Another condition related to Chromosome 18 is the 18p- syndrome, which is caused by deletions in the short arm of Chromosome 18 (18p). PubMed provides valuable resources and articles on the genetic and clinical aspects of this condition.
  • 18q Syndrome: The 18q syndrome, also known as distal 18q, is characterized by deletions in the long arm of Chromosome 18 (18q). Scientific articles on PubMed explore the genetic and clinical features of this syndrome, providing valuable information for early diagnosis and management.
  • 18p Tetrasomy: In some cases, individuals may have an extra copy of the proximal end of Chromosome 18 (18p). PubMed features scientific articles discussing the clinical and molecular findings associated with this rare condition.
  • 18q Trisomy: 18q trisomy refers to the presence of an additional copy of the long arm of Chromosome 18 (18q). PubMed contains research articles that delve into the genetic and clinical implications of this condition, offering valuable insights into diagnosing and managing individuals with this specific chromosomal abnormality.

These are just a few examples of the numerous scientific articles available on PubMed related to Chromosome 18. Researchers, clinicians, and individuals seeking information on this condition can rely on PubMed for up-to-date resources and research findings pertaining to the different genetic changes and health conditions associated with Chromosome 18.

References

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