GNPTAB


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GNPTAB

A gene on chromosome 12q23.2 that encodes two of three subunit types of the membrane-bound enzyme N-acetylglucosamine-1-phosphotransferase, a heterohexameric complex composed of 2 alpha, 2 beta and 2 gamma subunits. The encoded protein is proteolytically cleaved to yield mature alpha and beta polypeptides (the gamma subunits are the product of GNPTG). In the Golgi apparatus, the complex catalyses the first step in the synthesis of mannose 6-phosphate recognition markers on oligosaccharides of lysosomal enzyme, which are essential for lysosomal enzyme-targeted trafficking. 

Molecular pathology
GNPTAB mutations are linked to mucolipidosis II (I cell disease) and mucolipidosis IIIA (pseudoHurler polydystrophy).
References in periodicals archive ?
If future research confirms that stuttering in people with GNPTAB mutations derives from a loss of astrocytes in the brain, these findings could open the door to new therapeutic strategies for some people with persistent developmental stuttering by targeting associated molecular pathways and cells.
It is a product of 2 separate, unlinked genes: GNPTAB, on chromosome 12q23.3, and GNPTG, on chromosome 16p13.3.
Contemporary Nomenclature for ML II and ML III (a) Disorder Affected Gene Chromosome ML II [alpha]/[beta] GNPTAB 12q23.3 ML III [alpha]/[beta] GNPTAB 12q23.3 ML III [gamma] GNPTG 16p13.3 Disorder Previous Nomenclature ML II [alpha]/[beta] ML II, I-cell disease ML III [alpha]/[beta] ML IIIA, Pseudo-Hurler polydystrophy ML III [gamma] ML IIIC, ML III variant Abbreviations: ML II, mucolipidosis type II; ML III, mucolipidosis type III.
They also identified three other mutations in the GNPTAB gene which showed up in several unrelated individuals who stutter but not in the controls.