Down syndrome: clinical and cytogenetic analysis

To describe the clinical features and cytogenetic analysis of patients with Down syndrome (DS).

An observational study.

The Departments of Paediatrics and Internal Medicine of Military Hospital, Rawalpindi (MH, RWP) from January 1998 to December 2001.

Two hundred and ninety-five children <18 years of age clinically diagnosed as DS were included. The clinical presentation features, associated anomalies and maternal characteristics were noted.

Out of 295, 170 boys and 125 girls had chromosomal findings consistent with the diagnosis of DS. The mean presentation age was 16.2 months while 49 (16.6%) children presented in the neonatal period and 124 (42%) in infancy. Mongoloid slant, epicanthal folds, hypertelorism, simian crease, flat nasal bridge, and microcephaly were observed in >60% of cases. Congenital heart disease was documented in 103 (34.9%) cases and ventricular septal defect was the commonest cardiac anomaly. The cytogenetic analysis revealed that 282 (95.6%) had trisomy 21, 11(3.7%) had translocation, and only 2(0.7%) were mosaic. The mean maternal age was 29.8 years. One hundred and sixty (56.7%) cases with trisomy 21 had maternal age> 35 years, whereas 9/11(81.8%) cases of translocation had maternal age < 35 years.

The cytogenetic pattern of DS was similar to previously described series. Inadequate antenatal screening and scarce neonatal examination results in late presentation of DS. Majority of cases can be diagnosed on the clinical features of DS.