Newborn laboratory screening and diagnosis of patients with spinal muscular atrophy

Czech version

Authors: B. Lauerová ¹; M. Rohlenová ¹; A. Dolanská ¹; M. Gloser ¹; D. Pazdírek ¹; E. Vyhnálková ²; P. Hedvičáková ²; L. Juříková ³; O. Havlín ³; L. Dvořáková ⁴; P. Chrastina ⁴; K. Pešková ⁴; Z. Hrubá ⁵; J. Haberlová ¹
Authors‘ workplace: Klinika dětské neurologie 2. LF UK a FNMH, Praha ¹; Ústav biologie a lékařské genetiky 2. LF UK a FNMH, Praha ²; Klinika dětské neurologie LF MU a FN Brno ³; Diagnostické laboratoře dědičných poruch metabolismu, Klinika pediatrie a dědičných poruch metabolismu 1. LF UK a VFN v Praze ⁴; Centrum molekulární biologie a genetiky IHOK LF MU a FN Brno ⁵
Published in: Cesk Slov Neurol N 2026; 89(S1): 14-18
doi: https://doi.org/10.48095/cccsnn2026S14

Overview

Spinal muscular atrophy (SMA), specifically the 5q-linked form, is a severe autosomal recessive neurodegenerative disease in which the onset of clinical symptoms reflects an already ongoing, irreversible loss of motor neurons. The availability of causal treatment has significantly increased the importance of early diagnosis, ideally before symptoms develop. Newborn laboratory screening for SMA is based on the analysis of DNA from a dried blood spot using qPCR to detect a homozygous deletion of exon 7 of the SMN1 gene, which is the most common genetic cause of the disease. A positive screening result is not a definitive diagnosis and requires urgent confirmatory molecular genetic testing, including determination of the copy number of the SMN2 gene, clinical evaluation of the newborn, and a rapid decision on further treatment at a specialized neuromuscular center. In the Czech Republic, laboratory screening for SMA in newborns was first introduced as part of a nationwide pilot program in 2022–2023 and has been a standard component of the routine screening program since January 1, 2024. From the start of the pilot program through May 1, 2026, 41 patients with a genetically confirmed diagnosis of SMA were identified. The experience gained confirms the program’s high effectiveness and practical feasibility; however, it also highlights its limitations, particularly the inability to detect approximately 5% of patients with less common genetic variants of the SMN1 gene and the presence of clinical signs as early as the neonatal period in the most severe forms of the disease. Minimizing the delay between screening detection, confirmation of the diagnosis, and initiation of the causal therapy remains a fundamental prerequisite for optimal treatment outcomes.

Keywords:

spinal muscular atrophy – SMN1 – SMN2 – causal therapy – newborn screening – SMN protein – molecular genetic diagnosis – presymptomatic treatment

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