A pair of 2-year-old female monozygotic twins presented with short and brittle hair. There was marked reduction in hair density, and excessive curving of the eyelashes. Onychodystrophy was also evident. They also had developmental delay in verbal and motor skills. Neither their parents nor other relatives were known to be affected, and there was no history of consanguinity. Examination of the hair shaft under light microscopy showed trichoschisis, which was more evident under electron microscopy. Under polarized light, the hair shafts showed the pathognomonic 'tiger-tail' pattern. The level of sulphur in the hair was low. Both patients were negative for TTDN1 mutation. Clinical correlation was performed and the diagnosis of Sabinas syndrome was made. Sabinas syndrome is a very rare autosomal recessive disorder first described in a group of patients from a small community in north-eastern Mexico. It is diagnosable at birth, and its major symptoms include brittle hair, mental retardation and nail dysplasia. Structural hair abnormalities are seen by both light and electron microscopy.