Albinism or congenital nystagmus

Gene: SACS

Green List (high evidence)

Initial gene list and info collated by Jonathan Callaway (Wessex Regional Genetics Laboratory) February 2019. Suggested intial gene rating: Green; Comments provided: Comments from OMIM: Nystagmus is one of the features of Spastic ataxia, Charlevoix-Saguenay type (also known as ARSACS). Comments from HGMDpro: 264 variants listed, including numerous LOF variants. The majority have Spastic ataxia, Charlevoix-Saguenay type as the reported phenotype. Only 2 variants have a phenotype which in which nystagmus is specifically stated and this is as part of an ataxia phenotype (two missense variants, both reported by Blumkin et al 2015); there is no reference to albinism/hypopigmentation/foveal hypoplasia. However, genereviews for Spastic ataxia, Charlevoix-Saguenay type (also known as ARSACS) states that gaze-evoked nystagmus is one of common neurological signs. Therefore, there could be an argument for inclusion in the A&N panel. Although note that the ARSACS phenotype is specific and very different to that of the other A&N genes (ataxia, dysarthria, spasticity, extensor plantar reflexes, distal muscle wasting, a distal sensorimotor neuropathy predominant in the legs, and horizontal gaze-evoked nystagmus).

Created: 13 Feb 2019, 11:41 a.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Spastic ataxia, Charlevoix-Saguenay type 270550 AR