Partial 4q trisomy. Apropos of 3 cases

Area of Science:

• Genetics
• Clinical Dysmorphology
• Human Molecular Genetics

Background:

• Partial trisomy 4q, a chromosomal abnormality, results from an extra copy of a segment of the long arm of chromosome 4.
• Understanding the phenotypic spectrum associated with trisomy 4q is crucial for accurate diagnosis and genetic counseling.
• This condition can arise from various mechanisms, including translocations and duplications.

Observation:

• Three new cases of partial trisomy 4q were documented, involving familial translocation, de novo translocation, and a mirror duplication.
• A characteristic facial phenotype was observed across these patients.
• Specific dysmorphic features noted include an absent or poorly defined nasal bridge, pursed lips, a short philtrum, and a continuous fold from the antitragus to the earlobe.

Findings:

• The observed phenotype in the three new cases aligns with previously reported patients with partial trisomy 4q.
• The consistent presence of specific facial features suggests a recognizable syndrome associated with this chromosomal aberration.
• The genetic mechanisms (familial translocation, de novo translocation, mirror duplication) leading to partial trisomy 4q can result in a similar clinical presentation.

Implications:

• Recognition of this characteristic phenotype can aid in the early diagnosis of partial trisomy 4q.
• Accurate diagnosis facilitates appropriate genetic counseling for affected families.
• Further research into the specific genes on chromosome 4q involved in this phenotype may reveal underlying developmental pathways.