Intellectual disability in Indian children: experience with a stratified approach for etiological diagnosis.

Objective: To study the clinico-etiological profile of children with intellectual disability using an algorithmic approach. Design: Cross-sectional study. Setting: Tertiary care centre in Northern India. Participants: Consecutive children aged 3 months to 12 years, presenting with intellectual disability, confirmed by Developmental Assessment Scale for Indian Infants, Binet Kulshreshtha Test and Vineland Social Maturity Scale. Method: All children were assessed on an internally validated structured proforma. A targeted approach included thyroid function tests, Brainstem evoked response audiometry, electroencephalogram, neuroimaging and metabolic screen done as a pre-decided schema. Genetic tests included karyotyping, molecular studies for Fragile X, Multiplex Ligation Dependent Probe Amplification and Array Comparative Genomic Hybridisation. Results: Data of 101 children (median age 22 months) was analyzed. The etiological yield was 82.1% with genetic causes being the most common (61.4%) followed by perinatal acquired (20.4%), CNS malformations (12%), external prenatal (3.6%), and postnatal acquired (2.4%). Mild delay was seen in 11.7%, moderate in 21.7%, severe in 30.6% and profound in 35.6%. Conclusion: It is possible to ascertain the diagnosis in most of the cases of intellectual disability using a judicious and sequential battery of tests. [ABSTRACT FROM AUTHOR]