A review of Spinal Muscular Atrophy (SMA) in Black South African paediatric patients.

Abstract

Background: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder that is present in all populations and results in muscle weakness due to anterior horn cell degeneration. SMA is divided into three clinical subtypes and is an important genetic cause of morbidity and mortality but has not been well studied in sub-Saharan Africa.

Objective: The aim of this study is to describe the clinical features and genetic findings in black patients with SMA presenting to the Division of Paediatric Neurology at Chris Hani Baragwanath Academic Hospital (CHBAH) over a 30-year period.

Method: This study was a retrospective review of patient records. The study population was black paediatric neurology patients with clinical SMA, who attended CHBAH Neurology clinic between 1988 and 2018. Patients were categorized into SMA type 1, 2 or 3 based on the neurology assessment and clinical features were recorded.

Results: The clinical findings in the black South African patients with SMA were similar to those found in international studies. There were 131 patients fulfilling the inclusion criteria seen over a 30-year period at CHBAH, 86 of who had genetic testing. 84.8% of the genetic results for these patients were positive, which is significantly higher than previously reported in SA. 23.6% of patients had facial involvement.

Conclusions: This study adds to the limited body of research on SMA in subSaharan Africa and highlights the lower frequency of a homozygous deletion seen inthe black South African population when compared to the expected 95% worldwide. Word count: 248