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[Partial trisomy 14q II.--Partial trisomy 14q due to a maternal t(12; 14) (q24.4; q21)]
Insights
This study details a rare genetic condition, chromosome 14 partial trisomy, in an infant. Key features include developmental delays and distinctive facial characteristics, linked to a familial translocation.
Area of Science:
- Genetics
- Human Phenotype Studies
- Chromosomal Abnormalities
Background:
- Trisomy of chromosome 14, specifically the proximal portion of the long arm (14q), is a rare chromosomal abnormality.
- Familial translocations can lead to partial trisomies and recurrent genetic conditions within families.
- Understanding the phenotypic consequences of specific chromosomal duplications is crucial for genetic counseling and diagnosis.
Observation:
- An 18-month-old male infant presented with psychomotor and growth retardation.
- The infant exhibited an oval, dysmorphic facial appearance, characterized by a distinctive mouth and prominent nose.
- This phenotype was associated with trisomy for a segment of chromosome 14q.
Findings:
- The child's trisomy 14q resulted from a balanced translocation, t(12;14)(q24.4;q21), inherited from his mother.
- The translocation has been identified in at least three generations of the family.
- A minimal 12q duplication present in the child did not appear to contribute to the observed phenotype.
Implications:
- This case expands the understanding of phenotypes associated with partial trisomy 14q.
- Identifying familial translocations is vital for accurate genetic diagnosis and recurrence risk assessment.
- Further research can elucidate the specific genes on chromosome 14q responsible for these developmental and facial features.
Abstract:
The phenotype of an 18-month-old male infant trisomic for the proximal portion of the long arm of chromosome 14 was reported and compared with that of previously reported cases. For the identification of the resulting syndrome, the most consistent features are psychomotor and growth retardation, and an oval, dysmorphic facies which includes a distinctive form of the mouth and a prominent nose. The trisomy in the child reported here is due to a familial translocation transmitted by the mother and present in at least three generations: t(12;14)(q24.4;q21). The 12q duplication in the child's genome is minimal and does not seem to have contributed to his phenotype.