Inclusive gene testing assists accurate diagnosis
Machado-Joseph disease (MJD) can look like spastic paraplegia where there is no evidence of ataxia. Subsequent gene testing to confirm HSP will therefore yield no results. This research suggests considering gene testing for MJD in such cases.
The aim of the present study was to conduct a familial investigation and provide a genetic diagnosis to a family presenting with spastic paraplegia and clinically diagnosed with hereditary spastic paraplegia (HSP).
Blood samples were obtained from the family, and mutations in the gene causing spinocerebellar ataxia type 3 (SCA3)/Machado-Joseph disease (MJD), known as MJD1, were analyzed using the polymerase chain reaction, 8% denaturing polyacrylamide gel electrophoresis, and T-vector ligation and sequencing.
The trinucleotide repeat number of the mutant allele was 80, leading to a genetic diagnosis of SCA3/MJD. This suggests that patients with SCA3/MJD characteristically present with typical spastic paraplegia without evident manifestations of ataxia. For those families with HSP involving the nervous system and showing genetic anticipation, an MJD1 genetic diagnosis should be considered to assist in clinical diagnosis of HSP.
SOURCE: Exp Ther Med. 2015 Feb;9(2):417-420. Epub 2014 Dec 16. PMID: 25574208 [PubMed] PMCID: PMC4280951
Spinocerebellar ataxia type 3/Machado-Joseph disease manifested as spastic paraplegia: A clinical and genetic study.
Song Y1, Liu Y1, Zhang N1, Long L1.
1Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China.