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

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

Birth defects surveillance study.

OBJECTIVE: To study the overall frequency of congenital malformations in a city hospital in the first three days of life. METHODS: 17,653 consecutive newborns were examined and diagnosed at a maternity hospital by pediatricians and geneticists. Relevant information was documented on a predesigned proforma and analyzed. RESULTS: Of the 17,653 births 294 (1; 6%) had major malformations and 1400 (7.92%) had minor malformations. Amongst 17,653 births 328 (1.8%) were stillbirths. Malformations were highest in this group. Polygenic traits accounted for 45.1% while chromosomal etiology was found in 4%. A genetic basis was found in 65.4% of cases. CONCLUSION: With emphasis on ''small family '' norms & population control it is necessary to identify malformations so that Interventional programmes can be planned.