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

Abstract

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.

The genetic landscape of mitochondrial diseases in the next-generation sequencing era: a Portuguese cohort study

“…The mortality rate in our cohort (6%) was below the range of 14%-46% described in several other studies looking into MD mortality (Debray et al, 2007;Eom et al, 2017;Papadopoulos et al, 2020;Wong et al, 2023). Of the 62% deceased patients with a molecular diagnosis, the majority were children and presented mutations in the nuclear genes involved in mitochondrial translation.…”

Clinical Approaches for Mitochondrial Diseases

“…Yet, due to the difficulty of isolating individual mitochondria, there is a greater demand for studies to reveal the ambiguous dynamics of the mitochondrial processing of mtDNA. One thing that is not ambiguous is the notable prevalence of mitochondrial diseases [13][14][15]. Therefore, we are facing the need to solve this threatening problem affecting our populations.…”