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Partial trisomy 12q24.31----qter
Insights
This study details a male child with partial trisomy of the distal 12q chromosome region, identifying associated developmental and physical abnormalities. The findings contribute to understanding this rare genetic condition and its clinical manifestations.
Area of Science:
- Genetics
- Clinical Genetics
- Human Genetics
Background:
- Partial trisomy of chromosome 12q, specifically the distal region, is a rare chromosomal abnormality.
- Maternal balanced translocations, particularly involving the 4;12 translocation, are a common cause.
- Understanding the phenotypic spectrum is crucial for genetic counseling and diagnosis.
Observation:
- A male infant with karyotype 46,XY,-4,+der(4),t(4;12)(p16;q24.31)mat presented with a distinct set of clinical features.
- Key features included mental and psychomotor retardation, dysmorphic facial features (hypertelorism, flat nasal bridge, low-set ears, downturned mouth, micrognathia), and other anomalies.
- Additional findings encompassed loose nuchal skin, widely spaced nipples, simian creases, clinodactyly, genitourinary abnormalities, sacrococcygeal alterations, and lower limb deformities.
Findings:
- The reported case aligns with previously documented cases of distal 12q partial trisomy.
- The breakpoint in the majority of cases, including this one, is located in the 12q24 region.
- Adjacent 1 segregation of a maternal balanced translocation was identified as the mechanism.
Implications:
- This case expands the clinical description of partial trisomy 12q distal.
- Accurate karyotyping and genetic analysis are vital for diagnosing and managing affected individuals.
- Further research can elucidate genotype-phenotype correlations for better prediction of outcomes.
Abstract:
Clinical details of a male child with the karyotype 46,XY,-4,+der(4),t(4;12) (p16;q24.31)mat are reported and compared with those of other known cases of partial trisomy of the distal region of 12q. This condition is apparently associated with mental and psychomotor retardation, widely spaced eyes, flat nasal bridge, low set ears, down-turned mouth, micrognathia, loose skin at the nape, widely spaced nipples, simian creases, clinodactyly, abnormalities of the genitourinary system, alterations in the sacrococcygeal region, and deformities of the lower limbs. In the majority of the reported cases, the break-point was in the 12q24 region and resulted from adjacent 1 segregation of a maternal balanced translocation.