Ann Lab Med.  2013 May;33(3):221-224. 10.3343/alm.2013.33.3.221.

A Novel Mutation (c.200T>C) in the NAGLU Gene of a Korean Patient with Mucopolysaccharidosis IIIB

• Kim YE
• Park HD
• Jang MA
• Ki CS
• Lee SY
• Kim JW
• Cho SY
• Jin DK

• KMID: 1781332
• DOI: http://doi.org/10.3343/alm.2013.33.3.221

Abstract

Mucopolysaccharidosis (MPS) IIIB is a lysosomal storage disorder (LSD) caused by abnormalities of the enzyme alpha-N-acetylglucosaminidase (NAGLU) that is required for degradation of heparan sulfate. The patient in this study was a 4-yr-old boy. He presented with normal height and weight, pectus carinatum, and multiple persistent Mongolian spots on his back. He had mild dysmorphic features with prominent speech developmental delays and, to a lesser extent, motor developmental delays. The cetylpyridinium chloride precipitation test revealed excessive mucopolysacchariduria (657.2 mg glycosaminoglycan/g creatinine; reference range, <175 mg glycosaminoglycan/g creatinine). Thin layer chromatography showed urinary heparan sulfate excretion. NAGLU enzyme activity was significantly decreased in leukocytes (not detected; reference range, 0.9-1.51 nmol/hr/mg protein) as well as in plasma (0.14 nmol/hr/mg protein; reference range, 22.3-60.9 nmol/hr/mg protein). PCR and direct sequencing analysis of the NAGLU gene showed that the patient was a compound heterozygote for 2 mutations: c.200T>C (p.L67P) and c.1444C>T (p.R482W). The c.200T>C mutation was a novel finding. This is the first report of a Korean patient with MPS IIIB who was confirmed by molecular genetic analyses and biochemical investigation.

Keyword

Korean; Mucopolysaccharidosis IIIB; NAGLU; Novel mutation

MeSH Terms

Acetylglucosaminidase/blood/*genetics
Alleles
Asian Continental Ancestry Group/*genetics
Child, Preschool
Chromatography, Thin Layer
Heterozygote
Humans
Leukocytes/metabolism
Male
Mucopolysaccharidosis III/diagnosis/*genetics
Mutation
Polymerase Chain Reaction
Republic of Korea
Sequence Analysis, DNA
Acetylglucosaminidase

Figure

• 

  Fig. 1 NAGLU mutations detected by PCR sequencing analyses. The patient was a compound heterozygote for c.1444C>T (p.R482W) and c.200T>C (p.L67P).Abbreviation: NAGLU, α-N-acetylglucosaminidase.

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