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Homozygosity in piebald trait.
M A Hultén1, M M Honeyman, A J Mayne
1Regional Cytogenetics Laboratory, East Birmingham Hospital.
Journal of Medical Genetics
|September 1, 1987
Summary
Consanguineous parents with the dominant piebald trait had a severely affected child, suggesting intermediate inheritance. This case highlights that family history of consanguinity doesn't always imply recessive inheritance.
Area of Science:
- Genetics
- Human Heredity
- Medical Genetics
Background:
- The piebald trait is typically inherited in an autosomal dominant pattern.
- Consanguinity in parents can sometimes suggest recessive inheritance patterns.
Observation:
- A family presented with a severely affected child born to consanguineous parents.
- The parents exhibited milder manifestations of the piebald trait compared to their child.
Findings:
- The child's severe phenotype, despite dominant inheritance in the family, suggests incomplete penetrance or variable expressivity.
- The case challenges the assumption that consanguinity automatically indicates recessive inheritance, demonstrating dominant inheritance with variable expressivity.
Implications:
- This case underscores the importance of considering dominant inheritance patterns even in consanguineous families.
- Understanding variable expressivity is crucial for accurate genetic counseling and diagnosis of piebald trait.
- Further research into the genetic mechanisms underlying variable expressivity in dominant traits is warranted.