Clinical patterns of neuronal migrational disorders and parental consanguinity.

The role of inheritance in neuronal migrational disorders is under intense investigation. Studies on neuronal migrational disorders (NMDs) from developing countries that have a high rate of parental consanguinity are lacking. The present study included 29 children (aged 15 days-12 years, mean age 1.4 years) who were diagnosed to have NMDs, from a non-selected population with seizures and non-selected population of cognitive developmental delay, in the period January 1994 to April 1997. Seventeen (58.6 per cent) patients had lissencephaly, four (13.8 per cent) patients had pachygyria, three (10.3 per cent) patients had neuronal heterotopia, four (13.8 per cent) patients had schizencephaly, one patient (3.4 per cent) had hemimegalencephaly, and 14 (48.2 per cent) patients with NMDs had other associated conditions. Lissencephalic patients had a high rate of parental consanguinity (88.2 per cent) and family history of possible similar cases (76.4 per cent). In conclusion, lissencephaly is probably the commonest neuronal migrational disorder in communities with a high rate of parental consanguinity, adding significant support to the literature on the genetic aetiology of lissencephaly.