ALG3-CDG (CDG-Id): Clinical, biochemical and molecular findings in two siblings

We describe two Vietnamese siblings with confirmed ALG3-CDG (CDG-Id) by molecular testing. As far as we are aware, they are the oldest reported patients in the literature at 15 and 21 years. They share similar clinical features with previously reported patients including facial dysmorphism, severe psychomotor retardation, microcephaly, seizures, and gastrointestinal symptoms. Furthermore, our sibling pair highlights the intrafamilial variability, the natural clinical course of ALG3-CDG (CDG-Id) and the benefit of reassessing patients with undiagnosed and complex syndromes, particularly when they present with neurological deterioration.