Congenital aniridia is due to deletions and point mutations in the PAX6 gene. We describe here a case of a mother and her two sons with a syndrome comprising congenital aniridia, ptosis, and slight mental retardation. The sons also show behavioral changes. The possibility of deletion around the PAX6 locus was excluded by polymorphism studies and fluorescence in situ hybridization analysis. Mutation screening of the PAX6 gene revealed the presence of a transversion C719A, resulting in the substitution of arginine for serine at residue 119. We suggest that this missense mutation is responsible both for aniridia and ptosis, and possibly also for the observed cognitive dysfunction in this family.