Autism Spectrum Disorder and Long-Term Survival in Attenuated Molybdenum Cofactor Deficiency Type A: A Case Report From Saudi Arabia

TL;DR

An 18-year-old Saudi male with a rare genetic disorder shows a milder form of the disease, surviving into adulthood with autism and developmental delays.

Contribution

The case expands the known clinical spectrum of MoCD-A by demonstrating an attenuated phenotype with long-term survival and neuropsychiatric features.

Findings

The patient exhibited preserved motor function and seizure remission despite the genetic disorder.

Elevated urinary metabolites confirmed impaired sulfite oxidase activity in MoCD-A.

Neuroimaging showed a non-progressive focal hypodensity in the left basal ganglia.

Abstract

We report the case of an 18-year-old male with genetically confirmed molybdenum cofactor deficiency type A (MoCD-A) due to a homozygous pathogenic MOCS1 variant. He presented in infancy with hypotonia and developmental delay and experienced a generalized tonic seizure at 20 months of age, followed by long-term seizure remission. His clinical course was notable for preserved motor function, below-average cognitive ability, marked speech delay, autism spectrum disorder (ASD), and prominent inattentive symptoms. Metabolic testing demonstrated elevated urinary xanthine, hypoxanthine, and S-sulfocysteine levels, supporting impaired sulfite oxidase activity. Neuroimaging revealed a small, focal hypodensity in the left basal ganglia without progressive changes.

This case illustrates an attenuated phenotype of MoCD-A, with survival into adulthood and detailed neuropsychiatric characterization, expanding the recognized clinical spectrum and underscoring the importance of considering metabolic etiologies in patients with overlapping developmental and behavioral features.

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