COG5-congenital disorder of glycosylation diagnosed by whole genome sequencing in siblings with unexplained optic atrophy, macular atrophy, and developmental delay: case report - Report - MDSpire
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COG5-congenital disorder of glycosylation diagnosed by whole genome sequencing in siblings with unexplained optic atrophy, macular atrophy, and developmental delay: case report
Clinical Report: Diagnosis of COG5 Congenital Disorder of Glycosylation
Overview
This report details the diagnosis of COG5-CDG in two siblings presenting with unexplained optic atrophy, macular atrophy, and developmental delays. Whole genome sequencing (WGS) was essential in identifying the genetic variants responsible for their condition after other testing methods failed to provide a diagnosis.
Background
COG5-CDG is a rare autosomal recessive disorder that can lead to significant neurologic and ophthalmologic complications. The condition often presents with developmental delays and visual impairments, which can complicate diagnosis. Understanding the genetic basis of such disorders is crucial for proper management and counseling of affected families.
Data Highlights
No numerical data or trial data presented in the article.
Key Findings
Both siblings exhibited early-onset severe visual impairment and developmental delays.
Clinical features included bilateral optic atrophy, central macular atrophy, sensory nystagmus, and strabismus.
Whole genome sequencing identified compound heterozygous variants in the COG5 gene in both siblings.
One variant was a pathogenic frameshift, while the other was a deep intronic variant with predicted splicing impact.
Visual function remained stable over five years of follow-up.
This case expands the phenotypic spectrum of COG5-CDG to include concurrent optic nerve and macular involvement.
Clinical Implications
The findings underscore the importance of whole genome sequencing in diagnosing complex neuro-ophthalmologic conditions when traditional genetic testing is inconclusive. Clinicians should consider COG5-CDG in patients with unexplained developmental and visual impairments.
Conclusion
This case highlights the critical role of advanced genetic testing in identifying rare metabolic disorders and expanding the understanding of their clinical manifestations.
