Abstract
Background. Hypotonia is a common diagnostic challenge in pediatric neurology. This study aimed to determine the relative frequency of hypotonia etiologies in children after excluding cerebral palsy and seizure disorders.
Methods. This retrospective cross-sectional chart review was conducted at Tabriz Children's Hospital from April 2024 to April 2025. It included 102 children under 15 years diagnosed with hypotonia. Patients with cerebral palsy or seizure disorders were excluded from the study. Diagnosis was based on clinical examination, electrophysiology, neuroimaging, and genetic testing.
Results. The mean age of patients was 8.97±4.03 years, and gender distribution was equal. Consanguinity was found to be 22.5%, and positive family history was observed in 18.6% of the participants. Peripheral hypotonia was the most common type (58.82%), followed by central (12.74%) and mixed (13.73%). Fifteen patients (14.71%) remained undiagnosed. Spinal Muscular Atrophy (SMA) was the most common etiology (41 cases, 40.20%). Other etiologies included Guillain-Barré syndrome, myopathy, Duchenne muscular dystrophy, metabolic disorders, ataxia, transverse myelitis, acute flaccid myelitis, and pontocerebellar hypoplasia. Genetic testing confirmed diagnosis in 58 patients (56.86%). Consanguinity was significantly higher in SMA patients compared to others (35.7%, P=0.012).
Conclusion. Based on the results, peripheral hypotonia, particularly SMA, was predominant in this referral population. The high burden of genetic disorders, especially in consanguineous families, underscores the importance of prioritizing targeted genetic testing (SMN1 exon 7 deletion) and genetic counseling.
Practical Implications. Rapid diagnosis of SMA is of great importance. Clinicians should prioritize genetic testing for SMA in children with peripheral hypotonia, especially in high-consanguinity populations.