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A folate sensitive heritable fragile site at 19p13
Clinical Genetics
|May 1, 1985
Summary
A fragile site on chromosome 19p13 was identified in a mother of a child with Down syndrome. Its expression is sensitive to folate levels and specific chemicals, suggesting its potential use in genetic linkage studies.
Area of Science:
- Human Genetics
- Cytogenetics
- Molecular Biology
Background:
- Down syndrome is a genetic disorder associated with trisomy of chromosome 21.
- Fragile sites are specific points on chromosomes that are prone to breakage under certain conditions.
- Genetic linkage studies are crucial for mapping genes and understanding chromosomal abnormalities.
Observation:
- A specific fragile site was identified at the 19p13 chromosomal region in the maternal lineage of a newborn diagnosed with Down syndrome.
- The expression of this fragile site was observed to be dependent on the culture medium's folate concentration.
- The fragile site's expression was induced by 5-fluoro-2'-deoxyuridine (FdU) and inhibited by folate, thymidine, and thymidine analogs.
Findings:
- The fragile site at 19p13 exhibits differential expression influenced by folate availability and specific chemical agents.
- The observed inhibition by thymidine and its analogs suggests a mechanism related to DNA synthesis and folate metabolism.
- This specific fragile site's characteristics indicate a potential role in chromosomal instability.
Implications:
- The characterized fragile site at 19p13 could serve as a valuable genetic marker for future linkage studies on chromosome 19.
- Understanding the regulation of this fragile site may provide insights into the mechanisms underlying chromosomal abnormalities and genetic disorders.
- Further research into this fragile site could contribute to improved diagnostic and potentially therapeutic strategies for related genetic conditions.