A 25 year old patient who was known having tuberous sclerosis (ts) was referred by her neurologist to the psychiatric out-patient department because of behavioural and affective problems. After psychiatric evaluation, a semi-structured interview and a neuropsychological assessment, the diagnosis Pervasive Developmental Disorder Not Otherwise Specified (pdd-nos) was made. She started on long-term structured therapy. In the literature an association between pdd and ts has been well documented.