Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disease caused by a loss or mutation in the survival motor neuron 1 gene (SMN1) on chromosome 5q13, which leads to reduced SMN protein levels and a selective dysfunction of motor neurons. SMA is an autosomal recessive, early childhood disease with an incidence of approximately 1:10,000 live births and carriers is 1:50 in the population. Disease severity and clinical prognosis depends on the number of copies of SMN2. SMA is conventionally classified into 4 phenotypes on the basis of age of onset and highest motor function achieved. SMA Type 1 patients present with symptoms within the first 6 months of life and by definition never attain independent sitting. In contrast, SMA Type 2 manifests within the first 18 months of life and follows a slower disease progression as compared to SMA Type 1. Children with SMA Type 2 are able to maintain sitting unassisted but never walk independently and have a life expectancy of 20-40 years of age. SMA Type 3 patients attain the ability to walk unaided (Type 3a have onset <3 years of age; Type 3b have onset > 3 years of age). SMA Type 4 is an adult onset form of the disease. Recent therapeutic advances have given hope to families and patients by compensating for the deficiency in survival motor neuron (SMN) protein via gene therapy or other genetic manipulation. 721 Vietnamese patients with SMA during 20 years (2002-2022) were diagnosed and managed at the Vietnam National Children’s Hospital in Hanoi. Among them, 191 cases were diagnosed during recent 5 years (2016-2021). Subtypes distribution of 191 patients were 66 (34.6%) type I, 86 (45.1%) type II and 39 (20.3%) type III. The family history showed 42 (22%) children had a sibling with SMA. The diagnosed age of types I, II and III was 4.5 months, 2 years and 5.5 years, respectively. Progression of SMA type I was the most severe: 87.2% died at medium age of 10.5 months result from pneumonia and respiratory failure. 53% SMA type III were assisted sitting. 56.4% SMA type III did not walk. The scoliosisrate of SMA type I, II and III were 75%, 74% and 56%, respectively. In this report, the outcome of 23 patienst who received gene replecement therapy will be highted.
