Features include always present findings: Posteriorly rotated ears, Abnormal protein O-linked glycosylation, and Low-set ears; and very common findings: Seizure, Severe intellectual disability, Insomnia, and Decreased serum creatinine and others. 43 total HPO annotations.

GALNT2 encodes polypeptide N-acetylgalactosaminyltransferase 2 (571 aa). Catalyzes the initial reaction in O-linked oligosaccharide biosynthesis, the transfer of an N-acetyl-D-galactosamine residue to a serine or threonine residue on the protein receptor. Highest expression in Artery Aorta (91.0 TPM) and Cells Cultured fibroblasts (84.1 TPM).

Congenital disorder of glycosylation, type iit is strongly associated with mutations in the GALNT2 gene on chromosome 1.

GALNT2 is classified as a druggable target (Druggable Genome category) with score 5.8.

Genetic testing for GALNT2 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 3 always present features, 6 very common features, 6 common features.