Characterization of the SRD5A3-CDG Clinical Spectrum

Abstract

We aimed to characterize the clinical spectrum of patients diagnosed with SRD5A3-CDG, a subtype of congenital disorders of glycosylation (CDG) due to variants in the steroid 5a-reductase type 3 (SRD5A3) gene. It presents with multi-systemic involvement including neurological disability, dermatologic abnormalities, and ophthalmological defects. We conducted a cross-sectional study of children (n=6, ages 4-16 years) with a confirmed diagnosis of SRD5A3-CDG (c.57G>A, p.W19X). Families completed a detailed medical history questionnaire, two quality of life measures, and an adaptive behavior scale. Prevalent clinical features in our cohort included visual impairment (6/6), developmental delay (6/6), nystagmus (5/6), retinal dystrophy (4/6), and hypotonia (3/6). The Vineland Adaptive Behavior Scales demonstrated deficits across all functional domains (Composite Mean 36.17 ± 26.88), although one child did not show significant deficits. The QI-Disability Form demonstrated a mean total score of 64.8 (±12.7), and the PedsQL-Family Impact Module demonstrated a mean total score of 56.5 (±31.5). Vineland composite scores did not correlate with levels of disability captured by the QI-Disability Form (Pearson Correlation range -0.63 to +0.69, p>0.05 on all subscales). Ultimately, despite genotypic homogeneity, there is notable variability in adaptive functioning and quality of life among affected children that does not correlate with age.

Keywords:
Congenital disorder of glycosylation; SRD5A3; developmental delay; visual impairment; quality of life