This condition is caused by heterozygous mutations in the ACTG1 gene (17q25.3) and therefore transmitted in an autosomal dominant pattern. Sibs but no parental consanguinity has been reported. Both sexes are affected.
Mutations in the same gene are responsible for a somewhat similar condition known as Baraister-Winter 2 syndrome (614583).
Temtamy syndrome (218340) has some similar features but is caused by mutations in C12orf57 (12p13). In addition to microphthalmia and colobomas, intractable seizures, global delay and abnormalities of the corpus callosum are present.
Several patients that may have had this syndrome have had pericentric inversions of chromosome 2: inv(2)(p12q14). The PAX8 gene maps to the distal breakpoint of this inversion and may play a role as the location of a recessive mutation or as part of a submicroscopic inversion. No parent-child transmission has been reported.