Genetic counseling and prenatal diagnosis in India--experience at Sir Ganga Ram Hospital.

ABSTRACT

The experiences in genetic counseling and prenatal diagnosis at a tertiary genetic center in India are described. Of 3500 subjects provided genetic counseling 28.7% were for prenatal diagnosis, 13.7% for mental retardation +/- malformations, 11.5% for thalassemia, hemophilia and leukemia, 8.5% for neural tube defects and other malformations, and 8% for muscle dystrophy and spinal muscle atrophy. Chromosomal studies in blood (n = 5459) were for recurrent abortions (57.8%), delayed milestones (14.7%), malformations (11%), and infertility and amenorrhea (10.2%). Indications for amniotic fluid studies (n = 835) were advanced maternal age (35.7%), high risk result on triple test (21.3%), previous child with trisomy 21 (21.3%) and abnormalities seen on ultrasound (11.1%). Molecular studies were mostly for thalassemia (843, 24.3%), Duchenne muscular dystrophy (443, 12.5%), fragile X syndrome (367, 10.3%), spinal muscular atrophy (315, 8.9%), thrombophilia profile (233, 6.6%), triplet repeat disorders-spinocerebellar ataxias, Huntington disease and Friedreich ataxia-162 (4.6%), cystic fibrosis 140 (3.9%) and mitochondrial disorders 101 (2.9%). Other disorders for which molecular diagnosis was done were intrauterine infections by PCR on the amniotic fluid, Prader Willi/Angelman syndromes, hemophilia, achondroplasia, congenital adrenal hyperplasia, and Apert syndrome etc. In biochemical studies triple marker tests were the most common (3239), followed by aminoacid chromatography (774). Among neurolipidosis metachromatic leukodystrophy was the commonest, followed by Krabbe's disease, Tay Sach disease and Gaucher disease. Of the mucopolysacharidoses Hurler syndrome was the commonest, followed by Hunter syndrome. These data are compared with previous studies and a change towards increased prenatal diagnostic tests is observed. The commonest indication for amniocentesis has changed to advanced maternal age. CONCLUSION: Advanced molecular, cytogenetic and biochemical techniques have been a useful addition for genetic counseling and prenatal diagnosis in India.