Mandibular Distraction Osteogenesis in Monozygotic Twins With Structural-Dominant ALG8 Variants

Biallelic ALG8 mutations typically manifest as lethal multisystem congenital disorders of glycosylation (CDG-Ih). We report a unique case of monozygotic female twins presenting with Pierre Robin sequence (PRS) and orofacial-digital (OFD)-like features (cleft lip, tongue hamartomas, digital anomalies) without classic metabolic crises. Whole-exome sequencing identified compound heterozygous variants (c.140C>T and c.1349+1G>A). Severe airway obstruction was successfully managed through bilateral mandibular distraction osteogenesis (MDO), achieving complete respiratory weaning and oral feeding. This report provides critical evidence that specific ALG8 defects can manifest as a structural-dominant "metabolic ciliopathy," expanding the known phenotypic spectrum. Crucially for the craniofacial surgeon, this finding proves that MDO remains a safe, life-saving intervention even in complex genetic-metabolic backgrounds, providing a vital management precedent where theoretical risks of coagulation and bone metabolic issues might otherwise deter surgical intervention.