Ring chromosome 15: expanding the phenotype

Area of Science:

• Genetics
• Clinical Medicine
• Rare Diseases

Background:

• Ring chromosome 15 (R15) is an exceedingly rare chromosomal abnormality.
• Fewer than 50 cases have been documented in medical literature.

Observation:

• A patient presented with typical R15 features: growth retardation, hypertelorism, frontal bossing, high-arched palate, small extremities, and café-au-lait spots.
• The patient also exhibited mild intellectual disability, an atrial septal defect, and abnormal electroencephalogram (EEG) findings.

Findings:

• Two previously unreported clinical manifestations in R15 patients were observed: extensive hyperpigmentation on the anterior legs and feet, and hypogenesis of the corpus callosum.
• Conventional G-banding and fluorescence in situ hybridization (FISH) confirmed the diagnosis of ring chromosome 15.

Implications:

• This report expands the phenotypic spectrum associated with ring chromosome 15.
• Highlights the importance of comprehensive diagnostic evaluations for rare chromosomal disorders.
• Contributes novel observations to the understanding of R15 syndrome's genetic and clinical variability.