SACS variants are a relevant cause of autosomal recessive hereditary motor and sensory neuropathy
Mutations in the SACS gene have been initially reported in a rare autosomal recessive cerebellar ataxia syndrome featuring prominent cerebellar atrophy, spasticity and peripheral neuropathy as well as retinal abnormalities in some cases (autosomal recessive spastic ataxia of Charlevoix–Saguenay, ARSACS). In the past few years, the phenotypic spectrum has broadened, mainly owing to the availability and application of high-throughput genetic testing methods. We identified nine patients (three sib pairs, three singleton cases) with isolated, non-syndromic hereditary motor and sensory neuropathy (HMSN) who carried pathogenic SACS mutations, either in the homozygous or compound heterozygous state. None of the patients displayed spasticity or pyramidal signs. Ataxia, which was noted in only three patients, was consistent with a sensory ataxia. Nerve conduction and nerve biopsy studies showed mixed demyelinating and axonal neuropathy. Brain MRI scans were either normal or revealed isolated upper vermis atrophy of the cerebellum. Our findings confirm the broad clinical spectrum associated with SACS mutations, including pure polyneuropathy without characteristic clinical and brain imaging manifestations of ARSACS.
This work was supported by the German Federal Ministry of Education and Research (BMBF) through the German Network for Charcot-Marie-Tooth Neuropathies (CMT-Net) (01GM1511B, 01GM1511D, 01GM1511E; to Katharina Vill, Joachim Weis, Peter Young, Wolfgang Müller-Felber and Jan Senderek) and the Fritz-Thyssen-Stiftung (Az10.15.1.021MN; to Jan Senderek).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bergmann C, Zerres K, Senderek J, Rudnik-Schoneborn S, Eggermann T, Hausler M et al (2003) Oligophrenin 1 (OPHN1) gene mutation causes syndromic X-linked mental retardation with epilepsy, rostral ventricular enlargement and cerebellar hypoplasia. Brain: J Neurol 126(Pt 7):1537–1544CrossRefGoogle Scholar
- Vermeer S, van de Warrenburg BP, Kamsteeg EJ (1993) ARSACS. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A (eds) GeneReviews®. University of Washington, Seattle (WA)Google Scholar