Single-nucleotide polymorphism of transient axonal glycoprotein-1 and its correlation with clinical features and prognosis in chronic inflammatory demyelinating polyneuropathy.

The single-nucleotide polymorphism (SNP) rs2275697 in the transient axonal glycoprotein-1 (TAG-1) gene was reported to be associated with responsiveness to intravenous immunoglobulin (IVIG) treatment in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). However, it is not known if this SNP is associated with long-term prognosis. We examined the case records of 32 Chinese CIDP patients. The overall response rate to IVIG, prednisolone, or plasmapheresis was 83%. After 5.4 years, 57% of patients were on maintenance immunotherapy. Patients with higher modified Rankin score and more prolonged distal motor latencies in the upper limbs on presentation had a higher risk (odds ratio [OR] 3.86, 95% confidence interval [CI] 1.23-12.11 and OR 1.04, 95% CI 1.01-1.07, respectively) of being on maintenance immunotherapy. Blood samples from 24 patients and 147 controls were examined for their genotypes of four non-synonymous SNPs (rs41264871, rs36074532, rs5611135, and rs2275697) in the coding region of TAG-1. The G allelic frequency of rs2275697 was similar between CIDP patients and controls (56% and 50%, respectively) and was not associated with treatment responsiveness, treatment dependence, disability, or mortality.

Burden of rare variants in ALS genes influences survival in familial and sporadic ALS.

Genetic variants are implicated in the development of amyotrophic lateral sclerosis (ALS), but it is unclear whether the burden of rare variants in ALS genes has an effect on survival. We performed whole genome sequencing on 8 familial ALS (FALS) patients with superoxide dismutase 1 (SOD1) mutation and whole exome sequencing on 46 sporadic ALS (SALS) patients living in Hong Kong and found that 67% had at least 1 rare variant in the exons of 40 ALS genes; 22% had 2 or more. Patients with 2 or more rare variants had lower probability of survival than patients with 0 or 1 variant (p = 0.001). After adjusting for other factors, each additional rare variant increased the risk of respiratory failure or death by 60% (p = 0.0098). The presence of the rare variant was associated with the risk of ALS (Odds ratio 1.91, 95% confidence interval 1.03-3.61, p = 0.03), and ALS patients had higher rare variant burden than controls (MB, p = 0.004). Our findings support an oligogenic basis with the burden of rare variants affecting the development and survival of ALS.

Clinical phenotypes of a large Chinese multigenerational kindred with autosomal dominant familial ALS due to Ile149Thr SOD1 gene mutation.

About 10% of amyotrophic lateral sclerosis (ALS) cases are familial. We identified a five-generation Chinese family with autosomal dominant familial ALS (FALS). We performed a detailed family study, clinical and electromyographic validation, and SOD1, VEGF and CNTF mutation analyses. Forty-five living members (16 affected) were studied and DNA samples collected. Genealogical data were collected for deceased members. Based on the duration between symptom onset to ventilator dependence, they were divided into rapidly progressive (range 1-18 months, mean (SD) duration = 12.08 (+/-6.10) months, mean (SD) age of symptom onset = 39.75 (+/-9.84) years) and slowly progressive groups (>18 months; mean (SD) age of onset = 37.25 (+/-5.32) years old). We identified a heterozygous mutation of ATT to ACT of SOD1 gene at codon 149 in exon 5 resulting in substitution of isoleucine to threonine. It co-segregated with all affected members and 11 non-symptomatic members. We report a large multigenerational Chinese FALS kindred with I149T mutation in SOD1. No polymorphisms or mutations were found to date in two known modifier genes, namely, VEGF and CNTF, which were associated with heterogeneity in the phenotype within this kindred. Follow-up of the family will be helpful to explore any potential disease markers.