Dopa-responsive dystonia (DRD) is typically caused by heterozygous mutations in GTP cyclohydrolase 1 gene (GCH1). Our aim was to investigate the clinical and genetic features of Chinese DRD patients. We analyzed a cohort of Chinese DRD patients' clinical data. Mutation of the GCH1 gene was screened by direct sequencing. Additionally, multiplex ligation-dependent probe amplification (MLPA) assay targeting the GCH1 and the TH gene to evaluate large exon deletion or duplicate mutation of the genes were performed in point mutation-negative patients. Ten sporadic DRD patients and two pedigrees including six patients were included in the study. The onset age ranged from 3 to 15 years old. All patients initially presented with walking problems due to lower limb dystonia. The delay between onset and diagnosis ranged from 1 to 42 years old. The symptoms were completely or near-completely abolished with low dose levodopa treatment (dosages ranged from 25 mg to 400 mg/day). Direct sequencing in 14 patients found two known mutations (Gly203Arg in exon 5 in four unrelated patients and Met102Lys in exon 1 in one patient) and one new mutation (Thr186Ile mutation in exon 5 in two unrelated pedigrees). A heterozygous exon 2 deletion in the GCH1 gene was found in one of three point mutation-negative patients by MLPA analysis. Our clinical findings in DRD patients were consistent with other studies. GCH1 gene mutations were quite common in Chinese patients. MPLA should be performed in routine deletion analysis of GCH1 in point mutation-negative DRD patients.

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Our data on a cohort of Chinese patients show some difference from descriptions in other ethnic groups. This includes an earlier age of onset, a lower incidence of depression and female serving as a predictor factor of a HRQL. Similar to other cohorts, DYT1 gene mutations are rare.

The objective of this study was to analyse clinical and genetic features of patients with sporadic ALS in south-west China. All patients diagnosed with adult-onset sporadic ALS were consecutively followed up, and their clinical characteristics were collected. The frequencies of alleles of six SNPs in the FLJ10986 gene and the association between these SNPs and the clinical features of ALS were analysed. One hundred and sixty-one patients were included in the study. The mean age of onset was 50.9+/-11.4 years. The mean diagnostic delay was 16.5+/-14.3 months and the mean disease duration was 30.7+/-23.5 months. Forty patients (24.2%) died during the period of follow-up. Positive correlation between mean delay and disease duration was found, as was negative correlation between onset age, mean delay and disease duration. The frequency of the 'G' variant of the SNP (rs10493256) was significantly higher than that in a control population. There was no significant difference in the frequencies of variant alleles regarding clinical features. In conclusion, SNP (rs10493256) in the FLJ10986 gene appears to increase the risk of developing sporadic ALS in our Chinese population. Our Clinical findings are in line with other studies. No association between the polymorphisms and clinical features was found.

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