Mosaic cat eye syndrome in a child with unilateral iris coloboma

ABSTRACT

Background

Cat eye syndrome (CES) is a rare chromosomal disorder with a known incidence of 1 per 50,000–150,000 live newborns. The classic triad of iris coloboma, anorectal malformations, and auricular abnormalities is present in 40% of patients. In addition, other ocular malformations and systemic defects can be present. The aim of this report is to present a patient with unilateral iris coloboma related to a mosaicism of cat eye syndrome.

Methods

A complete ophthalmological and systemic evaluation was performed in a three-year-old male. He also underwent a standard karyotype and FISH analysis with a probe against the 22q11.2 locus.

Results

The ophthalmological and systemic evaluation revealed a unilateral iris coloboma and ipsilateral auricular malformations. Karyotype analysis of blood leukocytes indicated the presence of a marker chromosome in 6% of the analyzed cells. FISH analysis showed three positive signals in 5.5% of the analyzed nucleus.

Conclusion

This patient presented two of the three classic manifestations of CES; interestingly, they were unilateral. The 22q11 duplication was identified by standard karyotype and confirmed with FISH. The present case demonstrates the importance of conducting a multidisciplinary approach in patients with congenital malformations associated with known syndromes.

KEYWORDS:

• Cat eye syndrome
• chromosomal mosaicism
• iris coloboma
• fluorescent in situ hybridization
• karyotype

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.