Main clinical features:
Muscle / Neuromuscular: Congenital hypotonia, generalized weakness, poor neonatal movements, delayed motor milestones. Muscle biopsy shows centronuclear myopathy (increase frequency of central nuclei and hypertrophic myofibers) and myopathic changes with variation in fiber .
Cardiac: Dilated cardiomyopathy (DCM) is a hallmark phenotype for many pathogenic SPEGgenotypes and can be early-onset and progressive; dilation of the ventricles, mitral and tricuspid valve insufficiency, and other cardiac dysfunction are also reported.
Respiratory & feeding:Respiratory insufficiency and feeding difficulties are common in more severe neonatal presentations; need for ventilatory and feeding support via tracheostomy and gastrostomy tubes has been reported.
Onset & variability: Onset is typically neonatal or early infancy for the severe presentations; milder or later-onset phenotypes have also been described.
SPEG