Correlation analysis between genotype and phenotype of patients with facioscapulohumeral muscular dystrophy type 1

Abstract

Objective To investigate the clinical phenotype and genotype of facioscapulohumeral muscular dystrophy type 1 (FSHD1) and the correlation between the two. Methods The clinical data, genotype and laboratory examination of 25 patients with FSHD1 diagnosed by fluorescence in situ hybridization (FISH) from January 2017 to September 2018 were collected. Clinical Severity Score (CSS) was performed according to muscle involvement, and was corrected by age. Age-corrected CSS in 2 groups of patients with different 4qA D4Z4 repeat number was compared with two-independent-sample t test. The relation of D4Z4 repeat number with age-corrected CSS and age of onset were analyzed by using Spearman rank correlation analysis. Results The age-corrected CSS of patients with D4Z4 repeat number of 2-3 was significantly higher than that of patients with D4Z4 repeat number of 4-6. The age-corrected CSS of patients was negatively correlated with the number of D4Z4 repeat in 4qA (r = -0.619, P = 0.001) and the age of onset was positively correlated with the number of D4Z4 in 4qA (r = 0.516, P = 0.012). Conclusions The number of D4Z4 repeat in 4qA of FSHD1 patients is negatively correlated with the clinical severity. Genotype can help to indicate the clinical severity of FSHD1. At the same time, there are factors that affect the clinical severity of FSHD1 in addition to genotype. DOI: 10.3969/j.issn.1672-6731.2019.05.007

Keywords

• Muscular dystrophy, facioscapulohumeral
• Genotype
• Phenotype
• DNA copy number variations