An autosomal recessive mucolipidosis disorder caused by bi-allelic variants in the GNPTAB gene. Symptoms of this condition occur across a clinical spectrum including mucolipidosis type II (ML II) and mucolipidosis type III alpha/beta (ML IIIα/β), and phenotypes intermediate between ML II and ML IIIα/β. [ http://www.ncbi.nlm.nih.gov/pubmed/20301728 http://www.ncbi.nlm.nih.gov/pubmed/32651481 ]