A school based study of children with learning disability indicates poor levels of genetic investigation

Global learning disability (LD) is a neurodevelopmental defect in the capacity to acquire all or most learned higher mental skills that has a birth incidence of between 0.6% and 8% depending on case definition.1 LD shows extreme aetiological heterogeneity and can be the result of prenatal (most common and mostly genetic), perinatal (mostly hypoxic-ischaemic), or postnatal (mostly trauma or infective) onset disease processes. A specific diagnosis aids both accurate prognosis and genetic counselling but history and physical examination alone often cannot firmly establish the aetiology. In this situation, the consensus of expert opinion is that chromosome analysis and fragile X DNA testing be performed as minimum laboratory investigations.2 We wished to assess the completeness of these basic investigations in a community based population with LD. The study group was 128 children attending two state funded schools in north-east Edinburgh that provide special educational services for children without major physical handicap but with mild-moderate (IQ 50-70) or moderate-severe (IQ <50) LD. School 1 takes children aged 5-12 years and school 2 takes those aged 13-18 years. With written consent, 110 children (85.9%) were studied. They had a mean age of 12.3 years (range 5.8-17.9) and a male:female ratio of 67:43 (table 1). Hospital notes (both paediatric and clinical genetics) and community paediatric and school medical records were reviewed. Cytogenetic and DNA diagnostic reports were independently identified …