Neonatal molybdenum cofactor deficiency and ectopia lentis in a Saudi Arabian patient

Molybdenum cofactor deficiency (MCD) is a rare and ultimately fatal metabolic disease that results in extensive neurodegeneration in early infancy. The causal association of MCD with sulfite oxidase deficiency, a known cause of subluxed lenses (ectopia lentis), has only been recently defined. We report a 16-month-old Saudi Arabian male product of a consanguineous union, who presented as a neonate with intractable seizures and a failure to thrive. Subsequent examinations revealed hypotonia, laryngomalacia, global developmental delay, progressive neurodegeneration and ectopia lentis. Urine analysis revealed elevated sulfocystiene, xanthine and hypoxanthine, which suggested MCD. This diagnosis was confirmed by subsequent genetic analysis, which disclosed a homozygous MOCS1 mutation. A significant family history of sibling death, prior to diagnosis, from intractable seizures and respiratory distress at three months of age, most likely represents the same affliction and suggests an underestimation of MCD worldwide. This case underscores the need to consider and investigate MCD in all cases of intractable infantile seizures. Thus, early diagnosis and confirmatory gene analysis before permanent neurodegeneration is imperative for potential therapeutic intervention.