Abstract:

Intranuclear rod myopathy (IRM), a variant of nemaline myopathy, is characterized by the presence of nemaline bodies in myonuclei. We report a case of IRM presenting with hypoxic ischemic encephalopathy (HIE). There were no prenatal complications caused by fetal brain injury. Although no nemaline bodies were observed in the cytoplasm, intranuclear rods were observed in some fibers under light and electron microscopy. Molecular analysis identified a heterozygous variant, c.449C>T (p.Thr150Ile), in ACTA1. On magnetic resonance imaging at 9days of age, injuries to the basal ganglia, thalamus, and brainstem consistent with perinatal HIE were seen. Respiratory insufficiency at birth was strongly suspected to be the cause of HIE. Our case highlights that a patient with a congenital neuromuscular disorder who presents with severe respiratory dysfunction requiring substantial resuscitative efforts at birth can be complicated by HIE without any prenatal sentinel event. Prenatal detection of neuromuscular disorders, careful management of delivery, and neonatal resuscitation and adequate respiratory management are important in preventing irreversible brain injury in these patients.

日本語要旨:

低酸素性虚血性脳症を合併した核内ロッドマイオパチーの一例を報告した。筋生検により核内ロッドが見られ、ACTA1に変異(c.449C>T)が認められた。MRIにより生後9日の時点で低酸素性虚血性脳症(HIE)が認められた。出産前には、脳損傷によって引き起こされるような異常が認められなかったことから、HIEは出生時の呼吸不全によって引き起こされたものと考えられた。この症例は、出生前での神経筋疾患早期発見、綿密な出産管理、呼吸管理の重要性を示唆している。