[Partial trisomy 9p syndrome: Expanding the phenotype]

Area of Science:

• Genetics
• Chromosomal Abnormalities
• Medical Case Reports

Background:

• Trisomy of the short arm of chromosome 9 (9p) is a frequent autosomal structural anomaly, often resulting from parental translocations.
• Phenotypic variability in 9p trisomy is attributed to the size of the affected chromosomal segment.
• Rethoré syndrome, a form of partial trisomy 9p, is characterized by significant expressiveness and prognosis variability.

Observation:

• A patient presented with a karyotype indicating an additional fragment on chromosome 9p (46,XX,add(9)(p24)).
• Microarray analysis confirmed a triple dose in the 9p24.3-p13.1 region, consistent with partial trisomy 9p.
• The initial clinical presentation included a heart murmur leading to a diagnosis of pulmonary valve stenosis.

Findings:

• The identified chromosomal region (9p24.3-p13.1) in triple dose defines this case as partial trisomy 9p.
• Pulmonary valve stenosis was diagnosed in the patient, a cardiac anomaly not previously documented in the Rethoré syndrome phenotype.
• This finding suggests a broader spectrum of clinical manifestations for this condition.

Implications:

• Reporting novel clinical findings is crucial for expanding the documented phenotype of rare genetic disorders.
• Timely diagnosis of trisomy 9p and associated conditions can be improved by recognizing a wider range of clinical signs.
• Further research is warranted to understand the genetic basis and clinical spectrum of Rethoré syndrome and related 9p trisomies.