The changing scenario in prenatal diagnosis of genetic disorders: Genetics to genomics

Abstract

BackgroundPrevention of genetic disorders in the family is gaining significance because of the burden of these untreatable and devastating disorders. Sir Ganga Ram Hospital (SGRH) has been at the forefront for prenatal diagnosis (PND) in India for the last 2 decades. Aims and objectivesEvaluation of pregnant women for prenatal diagnosis in year 2017, and comparison with the centre's historical 5-year data published in 2003. Material and methodsPregnant women attending genetic clinics at SGRH and prenatal samples received from elsewhere were enrolled. Cytogenetic, molecular, biochemical and non-invasive methods were utilized for PND. ResultsAmong 3351 pregnant women from SGRH, 2530 presented with obstetric indications, and 821 women had a background family history. In cytogenetic laboratory, 706 prenatal samples from SGRH and 553 samples from elsewhere were analyzed. Additional 623 women opted for Non-invasive prenatal test (NIPT) for aneuploidies. In molecular genetics laboratory, 733 prenatal samples were analyzed. Highlights in the study included the introduction of NIPT, and other major advances - chromosomal microarrays and next-generation sequencing enabling PND in 130 and 20 cases, respectively. NIPT detected 10 cases of aneuploidy, with 10% false positivity in 623 women. Comparison with 5-year data from SGRH revealed a 6–10 fold rise in number of PNDs being performed, and addition of newer indications, materialized by newer methods of NGS and CMAs. ConclusionAdvanced genetic testing methodologies like NIPT, NGS and CMA are rapidly changing the scenario of prenatal diagnosis in our country, which is reflected in our data of last one year.