title: A mild form of mucolipidosis type III in four Baluch siblings.
abstract: Four Baluch siblings with mucolipidosis type III (pseudo-Hurler polydystrophy) are described. The patients had features commonly found in mucolipidosis III, including claw hands, joint stiffness, aortic valve involvement and radiological dysostosis multiplex. However, intelligence was normal, there were no eye abnormalities on slit-lamp examination and skin elasticity was normal. Many lysosomal enzymes were elevated in serum and diminished in cultured fibroblasts, although the findings for beta-galactosidase were atypical. Assays for the two enzymes involved in formation of the phosphomannose recognition marker revealed normal activity of the phosphotransferase with alpha-methylmannoside as an acceptor, and normal activity of the phosphodiester glycosidase. Metabolic labelling of fibroblasts with 32P followed by immunoprecipitation of cathepsin D, electrophoresis and fluorography showed that this enzyme was not labelled in the patients' cells, although some label was detected in the secreted precursor polypeptide. The data are consistent with the assumption that activity of the phosphotransferase is low towards lysosomal enzymes as substrates, and that the patients belong to complementation group C.
authors.affiliation: Paediatric Research Unit, UMDS, Guy's Hospital, London, UK.
authors.forename: C
authors.initials: C
authors.lastname: Ward
authors.forename: R
authors.initials: R
authors.lastname: Singh
authors.forename: C
authors.initials: C
authors.lastname: Slade
authors.forename: A H
authors.initials: AH
authors.lastname: Fensom
authors.forename: A
authors.initials: A
authors.lastname: Fahmy
authors.forename: A
authors.initials: A
authors.lastname: Semrin
authors.forename: A
authors.initials: A
authors.lastname: Sjövall
authors.forename: A
authors.initials: A
authors.lastname: Talat
authors.forename: A
authors.initials: A
authors.lastname: Hasilik
authors.forename: I
authors.initials: I
authors.lastname: Klein
mesh_terms: D001192:Arylsulfatases / Q000378:metabolism; D002402:Cathepsin D / Q000378:metabolism; D002648:Child; D005192:Family Health; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006026:Glycoside Hydrolases / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D009081:Mucolipidoses / Q000201:enzymology* / Q000208:ethnology / Q000235:genetics* / Q000473:pathology; D010770:Phosphotransferases / Q000378:metabolism; D011134:Polysaccharides / Q000652:urine; D011233:Precipitin Tests; D014479:United Arab Emirates
chemical_list: D011134:Polysaccharides; D010770:Phosphotransferases; D001192:Arylsulfatases; D006026:Glycoside Hydrolases; D002402:Cathepsin D