Mitochondrial diseases in Hong Kong: prevalence, clinical characteristics and genetic landscape.

OBJECTIVE: To determine the prevalence of mitochondrial diseases (MD) in Hong Kong (HK) and to evaluate the clinical characteristics and genetic landscape of MD patients in the region. METHODS: This study retrospectively reviewed the phenotypic and molecular characteristics of MD patients from participating public hospitals in HK between January 1985 to October 2020. Molecularly and/or enzymatically confirmed MD cases of any age were recruited via the Clinical Analysis and Reporting System (CDARS) using relevant keywords and/or International Classification of Disease (ICD) codes under the HK Hospital Authority or through the personal recollection of treating clinicians among the investigators. RESULTS: A total of 119 MD patients were recruited and analyzed in the study. The point prevalence of MD in HK was 1.02 in 100,000 people (95% confidence interval 0.81-1.28 in 100,000). 110 patients had molecularly proven MD and the other nine were diagnosed by OXPHOS enzymology analysis or mitochondrial DNA depletion analysis with unknown molecular basis. Pathogenic variants in the mitochondrial genome (72 patients) were more prevalent than those in the nuclear genome (38 patients) in our cohort. The most commonly involved organ system at disease onset was the neurological system, in which developmental delay, seizures or epilepsy, and stroke-like episodes were the most frequently reported presentations. The mortality rate in our cohort was 37%. CONCLUSION: This study is a territory-wide overview of the clinical and genetic characteristics of MD patients in a Chinese population, providing the first available prevalence rate of MD in Hong Kong. The findings of this study aim to facilitate future in-depth evaluation of MD and lay the foundation to establish a local MD registry.

Evaluation of sleep disturbances in children with epilepsy: a questionnaire-based case-control study.

Epilepsy is a chronic neurological disorder accompanied by a wide range of comorbid conditions that can adversely affect the quality of life of children. Sleep disturbances not only predispose children to mood, cognitive, and behavioral impairments, but also have a significant impact on physical health. The aim of this study was to evaluate sleep patterns among Chinese children with epilepsy and healthy subjects in Hong Kong, and examine the relationship between parent-reported sleep problems and specific epilepsy parameters. We conducted a cross-sectional, questionnaire-based, case-control study and included 63 children with epilepsy and 169 healthy children aged between 4 and 12 years. The Children's Sleep Habits Questionnaire (CSHQ) was used as an assessment tool. Our results indicated that children with epilepsy have similar sleep patterns but greater sleep disturbances compared with healthy subjects. Sleep problems should not be overlooked, and a comprehensive review of the sleep habits of this group of patients should be conducted.