Learning disability affects 3% of the population. Severe types of learning disability are more likely to have an underlying genetic cause but diagnosis is difficult because many different genetic abnormalities may be involved. Obtaining a diagnosis is important so that patients can be managed appropriately and their families can be given accurate information.

We aim to use new types of genetic testing which will make it possible to screen for several different genetic abnormalities which cause learning disability at the same time, so improving the accuracy and speed of diagnosis in the group of patients with severe learning disability. We will focus particularly on patients where seizures and behavioural problems are also present.This will enable more patients to be diagnosed accurately, reduce the number of hospital appointments needed and ultimately be more cost- effective.

Inclusion Criteria:

• Individuals with severe learning disability associated with either seizures, movement or behaviour problems who had previously undergone routine investigation but where no cause had been identified for their problems

Exclusion Criteria:

• Individuals with SLD where the cause is already known
• Individuals where informed consent cannot be obtained for participation

We will approach a cohort of patients with severe LD/seizures/behaviour problems who have presented to us in our genetic clinic for diagnosis over the past few years, but where the cause of their problems remains unknown. This will be our study population. In virtually all cases we will have performed routine diagnostic testing and will have stored DNA.