Colpocephaly is an abnormal congenital enlargement of the occipital horns of the lateral ventricles, which has typically been associated with learning disability, seizures, and motor and visual abnormalities. This study describes familial colpocephaly in two siblings with different fathers in a Dominican family. There were no other neurological problems in their relatives. Child 1 is a 7-year-old girl, who has had partial epileptic seizures since 4 years of age. She attends a mainstream school. She has coloboma and chorioretinic atrophy in her right eye and a right microphthalmia. MRI revealed colpocephaly and hypogenesis of the corpus callosum. Her brother, aged 2 years 8 months showed a mild delay in speech acquisition. He has had three febrile convulsions and two non-febrile tonic–clonic seizures since 6 months of age. Neurological and ophthalmological examinations were normal. MRI documented colpocephaly with right occipital horn prevalence. There are only two literature reports of genetically transmitted colpocephaly hypothesised in two identical twins and in two brothers. In the children in this study, a genetic basis for colpocephaly is confirmed. We hypothesised a maternal transmission with X-linked or autosomal dominance with an incomplete penetrance model of inheritance.