Autosomal dominant
Caused by a change in one copy of the ZSWIM6 gene. A recurrent change has been reported in several unrelated families. Some cases arise de novo, as a new change not inherited from either parent, and inheritance from a mildly affected parent with mosaic changes has also been reported.
Signs and symptoms
Frontonasal dysplasia, with widely spaced eyes and a broad or split nasal tip, together with limb differences such as extra big toes (preaxial polydactyly) and underdeveloped shin bones. Brain differences, including agenesis of the corpus callosum, and intellectual disability are also seen. Other brain malformations, such as encephalocele and interhemispheric lipoma, have been reported.
What a diagnosis changes
Care involves craniofacial and orthopaedic assessment, neurological review and developmental and educational support. Some cases arise de novo, so genetic counselling and parental testing help clarify recurrence risk.
Genes analysed
Also known as
AFND; frontonasal dysplasia acromelic; Toriello syndrome
