Clinical features, gene diagnosis and pedigree analysis of Huntington disease in Sichuan Province / 中国神经精神疾病杂志

ABSTRACT

Objective To investigate the clinical characteristics of families with Huntington disease in Sichuan, and to make genetic diagnosis and pedigree analysis, and to provide genetic counseling for family members. Methods The detailed clinical data of Huntington disease patients and some family members who visited were collected from provincial people's Hospital of Sichuan between March 2016 and March 2018. The CAG trinucleotide repeats of IT15 gene were examined. The mini mental state examination (MMSE), Montreal cognitive scale (MoCA) were used to evaluate the cognitive function. Hamilton anxiety scale (HAMA), Hamilton Depression scale (HAMD) were used to evaluate the emotion. Activities of daily living scale (ADL) were used to evaluate the ability of daily life. Results Genetic test was conducted on twenty-four individuals from 4 families. Genetic test detected eight HD patients with 41-54 CAG repeats (46.75±4.03) and seven presymptomatic patients with 43~58 CAG repeats (50.00 ±6.40). Four of HD patients required genetic counseling for marriage and childbearing. The number of normal CAG repeats was 12~24, with 17 and 20 being the most common. Correlation analysis found that the number of CAG repeats was negatively correlated with the age of onset (r=-0.967, P＜0.01). ADL score was positively correlated with course of disease (r=0.842, P＜0.01), and negatively correlated with MMSE score (r=-0.930, P＜0.01) and MoCA score (r=-0.932, P＜0.01). Conclusion Genetic test is of great significance in the diagnosis of Huntington's disease, especially in patients with negative family history. The number of CAG repeats is increase from generation to generation and there is genetic anticipation in HD families. The number of CAG repeats can predict the onset age to some extent. Genetic counseling and prenatal diagnosis are important to avoid the birth of a child with HD.