| Baraitser-Winter syndrome (BWS) is a malformation syndrome with characteristics of facial dysmorphism (hypertelorism with ptosis, broad bulbous nose, ridged metopic suture, arched eyebrows, progressive coarsening of the face), ocular coloboma, pachygyria and/or band heterotopias with antero-posterior gradient, progressive joint stiffening and intellectual deficit of variable severity, often with severe epilepsy. Pachygyria - epilepsy - intellectual disability - dysmorphism (Fryns-Aftimos (FA) syndrome) corresponds to the appearance of BWS in elderly patients. BWS and FA were initially considered separate entities. BWS is a genetically heterogeneous disorder, caused by a heterozygous mutation in one of the 2 genes coding for ubiquitously expressed actins: ACTB, located to 7p22-p12 (BRWS1) and ACTG1 on 17q25.3 (BRWS2). All mutations are missense and probably act by a gain of function mechanism, as deletions of the same genes do not result in BWS phenotype. All molecularly confirmed cases are sporadic, with, in theory, an autosomal dominant transmission, but effective transmission has never been reported. |
