NAGPA
NAGPA (N‑acetylglucosamine‑1‑phosphate uridyltransferase) is a soluble enzyme located in the Golgi apparatus that catalyzes the conversion of N‑acetylglucosamine‑1‑phosphate to the activated sugar nucleotide UDP‑N‑acetylglucosamine‑1‑phosphate. This reaction is a key step in the N‑glycosylation pathway that modifies lysosomal enzymes and plays a critical role in protein sorting and degradation. Deficiency of NAGPA leads to impaired processing of lysosomal hydrolases, resulting in the accumulation of undigested substrates and a spectrum of neurodevelopmental abnormalities.
The gene NAGPA is located on chromosome 9q34.2 and encodes a protein of approximately 40 kilodaltons. Heterozygous
Clinically, affected individuals may exhibit hypotonia in infancy that improves over time, but cognitive deficits persist.
Ongoing studies aim to clarify genotype‑phenotype correlations, determine the prevalence of NAGPA mutations in diverse populations,