Early genetic Diagnosis of Nemaline Myopathy Following Neonatal Hypotonia:

A Patient Report

Abstract

　　A female infant was born at 41 weeks of gestation with a birth weight of 3,380 g and Apgar scores of 8 and 9. She developed feeding difficulty and respiratory distress immediately after birth and was transferred to our neonatal unit on 1st day of life. Swallowing difficulty persisted after admission, and she frequently experienced oxygen desaturation and bradycardia. Nasal high-flow therapy and supplemental oxygen were administered but were insufficient. Brain magnetic resonance imaging, ordinary blood tests, urinary organic acid analysis, and genetic test for spinal muscular atrophy revealed no abnormalities. Chromosomal G-banding showed a normal female karyotype. As hypotonia and swallowing difficulty persisted, a congenital myopathy gene panel test (Kazusa DNS Res, Inst, Kisarazu, Japan) was performed. A known pathogenic variant in the skeletal alpha-actin 1 (ACTA1) gene (c.203C>T, p.Thr68Ile) was identified, she was diagnosed with nemaline myopathy. Nemaline myopathy is a congenital myopathy that can present with hypotonia, respiratory insufficiency, and feeding difficulties from neonatal period. Congenital myopathy gene testing is minimally invasive and may be useful for early diagnosis.