Chromosome 22 microdeletion by F.I.S.H. in isolated congenital heart disease

To analyze the frequency of del22q11.2 in non-syndromic CHDs using classical cytogenetics and Fluorescence In Situ Hybridization (FISH) technique in Indian population.

105 prospective cases which included 6 families with isolated, non-syndromic cardiac defects were analyzed clinically by a cardiologist and a geneticist. The cases were then subjected to karyotypic (classical cytogenetics) as well as FISH analysis. The efficacy of FISH technique was compared with inference drawn from classical cytogenetics.

Karyotypic analysis of all the 105 patients revealed a normal chromosomal complement. Microdeletion 22q11.2 was observed in six patients (5.71%) by FISH studies. FISH studies were also performed on the parents of these six patients who revealed a normal chromosome 22. No correlation was found between clinical features (mild or unspecific) with 22q11.2 microdeletion.

The testing for microdeletion 22q11.2 in isolated non-syndromic patients using FISH technique is mandatory even when mild/unspecific extracardiac abnormalities are seen in the patients.