Genetic testing of adults with intellectual disability

Abstract

Method: Patients known to learning disability services in two health boards in southeast Scotland were cross-matched with the patients tested at the Western General Hospital in Edinburgh. Those with a positive genetic diagnosis were identified. Semistructured interviews were conducted with senior learning disability psychiatrists and clinical genetics consultants. Results: Of the 3323 patients with intellectual disability across both health boards, 41% have had genetic tests and 6% have an identified genetic abnormality as the cause for their intellectual disability. Of the 1349 patients who have been tested, a genetic abnormality was found in 14%. Psychiatrists named several benefits to genetic testing, but they also highlighted a number of non-medical reasons for not testing adults with intellectual disability. Clinical implications: Identifying genetic aetiology in intellectual disability has a number of benefits. Our study would indicate that genetic diagnoses are being missed due to a lack of genetic testing in this patient group. Adult learning disability services need to consider increasing genetic testing.