Diagnosis of genetic defects by chromosomal analysis.

Of 901 karyotypes performed over a period of 4 years, genetic anomalies were detected in 162 cases. Down's syndrome (trisomy 21) was the most common (168.8%) genetic disorder followed by Turner's syndrome, Philadelphia chromosome, Klinefelter's syndrome, Edward's syndrome (trisomy 18) and Patau's syndrome (trisomy 13). All the three trisomies were detected very early in life. Mean age at the time of diagnosis for Turner's syndrome was 13.3 years, allowing a timely hormone replacement therapy to improve secondary sexual characters. Patients with Klinefelter's syndrome were diagnosed late (mean age 23.6 years), which greatly reduced their chances of an effective therapy to improve the clinical and social outcome.