Features include always present findings: Metaphyseal widening, Pulmonary hypoplasia, Abnormal lung lobation, and Narrow greater sciatic notch and others; and very common findings: Polycystic kidney dysplasia, Microcephaly, Decreased skull ossification, and Proptosis. 35 total HPO annotations.

ALG9 encodes ALG9 alpha-1,2-mannosyltransferase (611 aa). Mannosyltransferase that operates in the biosynthetic pathway of dolichol-linked oligosaccharides, the glycan precursors employed in protein asparagine (N)-glycosylation. Highest expression in Nerve Tibial (12.8 TPM) and Cervix Ectocervix (12.7 TPM).

Gillessen-Kaesbach-Nishimura syndrome is associated with mutations in the ALG9 gene on chromosome 11.

The ALG9 protein participates in Defective ALG9 causes CDG-1l, Defective ALG12 causes CDG-1g, and Defective ALG6 causes CDG-1c pathways.

ALG9 is classified as a druggable target (Enzyme category) with score 0.0.

Genetic testing for ALG9 is available. Testing is considered confirmatory for diagnosis.

Phenotype severity distribution: 16 always present features, 4 very common features, 8 common features.