Interstitial deletion of the short arm of chromosome 7 without craniosynostosis

Area of Science:

• Genetics
• Human Genetics
• Clinical Genetics

Background:

• Structural abnormalities of chromosome 7, particularly deletions in the short arm (7p), can lead to diverse clinical presentations.
• Understanding genotype-phenotype correlations is crucial for diagnosing and managing genetic disorders.
• Previous reports have linked certain deletions on chromosome 7p to craniosynostosis.

Observation:

• Two female infants presented with apparently identical interstitial deletions of chromosome 7 bands p13 to p15.
• Despite similar karyotypic findings, the infants exhibited distinct phenotypes.
• Clinical features included developmental delay, dysmorphic facial features, and limb anomalies, varying between the two cases.

Findings:

• The observed phenotypes ranged from failure to thrive and developmental retardation to normal growth with unique features like widely spaced nipples and enlarged genitalia.
• Comparison with literature suggests that deletions encompassing 7p13-p15 are not associated with craniosynostosis.
• Craniosynostosis was noted in prior cases involving deletion specifically at band 7p14, differentiating it from the current findings.

Implications:

• These findings refine the understanding of the critical region for specific phenotypes on chromosome 7p.
• The study highlights the complexity of genotype-phenotype relationships in chromosomal deletion syndromes.
• It provides evidence against the association of 7p13-p15 deletions with craniosynostosis, aiding in differential diagnosis.