CLINICAL AND GENETIC CHARACTERISTICS OF PROXIMAL SPINAL MUSCULAR ATROPHY IN CHILDREN IN THE SOUTHERN REGIONS OF KAZAKHSTAN
This article contains a brief overview of clinical forms of spinal muscular atrophy (SMA) and highlights the results of original study aimed to characterize the clinical and genetic features of the disease in children in the southern regions of Kazakhstan. The study material was 30 patients with symptoms of SMA selected for the study from May 2017 to December 2018. A clinical, neurological and genetic study was carried out on the search for mutations in the SMN1 gene. Results of the study: 30 patients aged from 1 month to 15 years old, living in Almaty, Shymkent and Almaty cities, South Kazakhstan/Turkestan regions, boys - 13 (43.3%), girls - 17 (56.7%). The clinical genetic diagnosis of spinal muscular atrophy was first made out in 16 children (53.3%) and genetically confirmed in 14 of them (46.7%). Ranking by type of disease: SMA 0 type - 1 (3.3%), SMA 1 type - 8 (26.7%), SMA II type - 14 (46.7%), SMA III type - 7 (23.3 %). The majority is represented by patients of native citizens - 16 (53.3%). Family history revealed a consanguineous marriage of parents in 16.7% of cases and 23.3% of cases of SMA burden. All patients at the age of 1 year had a delay of motor development of varying severity: severe degree of delay was noted in 26.7%, medium - in 46.6%, mild - in 26.7%. Self-walking skills were studied in a group of children over 1 year old: 4 children (17.4%) developed at the age of 16 months, 5 (21.7%) developed at the age above 16 months, 14 children (60.9 %) self-walking skill is not achieved. Lesions symptoms of the proximal muscle groups of the upper and lower extremities dominate in the neurological status in the form of muscle weakness (96.7%, 100%), lack of patellar reflex (93.3%), reduced reflexes from the upper limbs (73.3%), tongue fibrillation (83.3%), and abdominal reflex pathology (100%). The paper presents a PCR-RFLP-based method to determine a homozygous deletion of 7 and 8 exons of the SMN1 gene in 23 children (76.7%), a homozygous deletion of exon 7 - 6 (20%), a homozygous deletion of exon 8 - 1 (3.3%). Late diagnosis of the disease and the lack of adequate rehabilitation care and multidisciplinary care led to a worsening of the neurological status and numerous complications of the bone and articular system in patients under observation. The problem of SMA in children in Kazakhstan requires further epidemiological and clinical studies on large populations of patients with the analysis of correlative relationships “phenotype-genotype” and the use of modern diagnostic tools.