PURPOSE: The mucopolysaccharidoses (MPSs) are a heterogeneous group of lysosomal storage disorders. They are caused by a deficiency of the enzymes involved in the degradation of glycosaminoglycans. Early recognition is important because recombinant enzyme replacement therapy is now available for MPS. We studied the clinical characteristics of 80 MPS children with the object of determining the epidemiological, clinical and radiological features in Korean MPS children. METHODS: Diagnosis of MPS was confirmed by skin fibroblast enzyme analysis in 80 patients between February 1995 and December 2004. Charts were retrospectively reviewed for clinical and radiological findings, as well as for intelligence and speech evaluations. RESULTS: Hunter syndrome (MPS type II) was the most prevalent type, appearing in 51/80 cases (64 %), followed by Sanfilippo syndrome (MPS III-18%), Hurler syndrome (MPS I-15%), and Morquio syndrome (MPS IV-4%). The average age at diagnosis was 5.5 years (range 1 to 20), and the male-to-female ratio was 4.7: 1. Typical radiographic changes were observed in 45/54 cases (83%). Mitral regurgitation was the most common cardiac defect. Moderate to profound mental retardation and hearing loss were present in 14/35 cases (56%) and 33/38 cases (82%), respectively. Four MPS II patients had bone marrow transplantation, with mixed outcomes. Five MPS I patients are currently on enzyme replacement therapy. CONCLUSION: Our study showed a high proportion of MPS II cases (64%), which may represent population variability. By studying the clinical features of these patients, we hope to alert pediatricians of the warning signs of MPS.
Bone Marrow Transplantation ; Child ; Diagnosis ; Enzyme Replacement Therapy ; Fibroblasts ; Glycosaminoglycans ; Hearing Loss ; Hope ; Humans ; Incidence ; Intellectual Disability ; Intelligence ; Korea ; Mitral Valve Insufficiency ; Mucopolysaccharidoses* ; Mucopolysaccharidosis I ; Mucopolysaccharidosis II ; Mucopolysaccharidosis III ; Mucopolysaccharidosis IV ; Retrospective Studies ; Skin

Mucopolysaccharidosis type III (MPS III) is a rare genetic disorder caused by lysosomal storage of heparan sulfate. MPS IIIB results from a deficiency in the enzyme alpha-N-acetyl-D-glucosaminidase (NAGLU). Affected patients begin showing behavioral changes, progressive profound mental retardation, and severe disability from the age of 2 to 6 years. We report a patient with MPS IIIB with a long-term follow-up duration. He showed normal development until 3 years. Subsequently, he presented behavioral changes, sleep disturbance, and progressive motor dysfunction. He had been hospitalized owing to recurrent pneumonia and epilepsy with severe cognitive dysfunction. The patient had compound heterozygous c.1444C>T (p.R482W) and c.1675G>T (p.D559Y) variants of NAGLU. Considering that individuals with MPS IIIB have less prominent facial features and skeletal changes, evaluation of long-term clinical course is important for diagnosis. Although no effective therapies for MPS IIIB have been developed yet, early and accurate diagnosis can provide important information for family planning in families at risk of the disorder.
Diagnosis ; Epilepsy ; Family Planning Services ; Follow-Up Studies ; Heparitin Sulfate ; Humans ; Intellectual Disability ; Lysosomal Storage Diseases ; Mucopolysaccharidoses* ; Mucopolysaccharidosis III* ; Pneumonia

OBJECTIVE: To explore the clinical and genetic characteristics of a patient with hypertrophic cardiomyopathy as the initial manifestation of Mucopolysaccharidosis type Ⅲ A (MPS Ⅲ A). METHODS: A female patient with MPS Ⅲ A who was admitted to the Affiliated Hospital of Jining Medical University in January 2022 and her family members (seven individuals from three generations) were selected as the study subjects. Clinical data of the proband were collected. Peripheral blood samples of the proband was collected and subjected to whole exome sequencing. Candidate variants were verified by Sanger sequencing. Heparan-N-sulfatase activity was determined for the disease associated with the variant site. RESULTS: The proband was a 49-year-old woman, for whom cardiac MRI has revealed significant thickening (up to 20 mm) of left ventricular wall and delayed gadolinium enhancement at the apical myocardium. Genetic testing revealed that she has harbored compound heterozygous variants in exon 17 of the SGSH gene, namely c.545G>A (p.Arg182His) and c.703G>A (p.Asp235Asn). Based on guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PM2_Supporting +PM3+PP1Strong+PP3+PP4; PS3+PM1+PM2_Supporting +PM3+PP3+PP4). Sanger sequencing confirmed that her mother was heterozygous for the c.545G>A (p.Arg182His) variant, whilst her father, sisters and her son were heterozygous for the c.703G>A (p.Asp235Asn) variant. Determination of blood leukocyte heparan-N-sulfatase activity suggested that the patient had a low level of 1.6 nmol/(g·h), whilst that of her father, elder and younger sisters and son were all in the normal range. CONCLUSION The compound heterozygous variants of the SGSH gene probably underlay the MPS ⅢA in this patient, for which hypertrophic cardiomyopathy is an associated phenotype.
Female ; Humans ; Cardiomyopathy, Hypertrophic ; Contrast Media ; East Asian People ; Gadolinium ; Mucopolysaccharidosis III ; Mutation ; Pedigree ; Male ; Middle Aged

OBJECTIVEMucopolysaccharidosis (MPS) types IIIA, B, C, D are a group of autosomal recessive lysosomal storage disorders caused by mutations in one of four genes which encode enzyme activities required for the lysosomal degradation of heparan sulfate. MPSIIIA and MPSIIIB involve deficiencies of heparan N-sulfatase (SGSH) and alpha-N-acetylglucosaminidase (NAGLU). MPS IIIA and MPS IIIB are more common than MPS IIIC and IIID. The present study aimed to establish two enzyme assay methods for SGSH and NAGLU activities for carrying out postnatal and prenatal diagnosis of MPSIIIA and IIIB by means of SGSH and NAGLU activity assay on plasma, leukocyte, uncultured chorionic villi (CV) and cultured amniotic fluid cells (AF cell) using two newly synthesized substrates. Mutation analysis of SGSH gene was also performed.

METHODSTwo fluorigenic substrate (4-methylumbelliferyl-alpha-D-N-sulphoglucosaminide.Na and 4-methylumbelliferyl-alpha-N-acetylglucosaminide) were used for the assay of SGSH and NAGLU activity. SGSH activity in leukocyte was determined for diagnosis MPSIIIA proband. NAGLU activity was determined in plasma for diagnosis of MPSIIIB proband. Twelve cases with MPS III were enrolled in this study, 4 were female and 8 were male, age 3 - 10 years and were from 10 unrelated families. Eight exons of SGSH gene were amplified by PCR. The mutations of the patients were characterized by direct sequencing of the amplified DNA fragments. Prenatal diagnosis in 3 pregnancies at risk was carried out according to NAGLU activity on uncultured CV at 11th week or on cultured AF cell at 18th week of gestation.

RESULTSThe SGSH activities in leukocyte of normal controls were 4.4 - 8.1 nmol/(17 h.mg protein). The NAGLU activity in plasma of normal controls was 33.3 - 62.4 nmol/(4 h.ml). The NAGLU activities were 44.9 - 91.7 nmol/(17 h.mg protein) and 53.2 - 82.2 nmol/(17 h.mg protein) in CV and cultured AF cells respectively. Five cases of MPS IIIB and 7 cases of MPS IIIA were diagnosed. The mutation analysis of SGSH gene showed 6 mutations (G191R, D235N, R377C, E447K, R233X and D219Wfs264X), only one of which (D219Wfs264X) has not been previously reported. Prenatal diagnosis was performed on 3 pregnancies at risk. NAGLU activity of one affected fetus was 1.5 nmol/(17 h.mg protein) in AF cell.

CONCLUSIONSThe method using synthesized fluorigenic 4-methylumbelliferyl-substrates were sensitive, rapid and convenient assay of SGSH and NAGLU activity and were reliable for early prenatal diagnosis. Mutation analysis on MPS IIIA patients suggests new possibilities for molecular diagnosis of the disease.

Acetylglucosaminidase ; genetics ; Child ; Child, Preschool ; DNA Mutational Analysis ; Diagnosis, Differential ; Female ; Humans ; Male ; Mucopolysaccharidosis III ; diagnosis ; genetics ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Sulfatases ; genetics

Mucopolysaccharidosis (MPS) III has 4 enzymatically distinct forms (A, B, C, and D), and MPS IIIC, also known as Sanfilippo C syndrome, is an autosomal recessive lysosomal storage disease caused by a deficiency of heparan acetyl-CoA:alpha-glucosaminide N-acetyltransferase (HGSNAT). Here, we report a case of MPS IIIC that was confirmed by molecular genetic analysis. The patient was a 2-yr-old girl presenting with skeletal deformity, hepatomegaly, and delayed motor development. Urinary excretion of glycosaminoglycan (GAG) was markedly elevated (984.4 mg GAG/g creatinine) compared with the age-specific reference range (<175 mg GAG/g creatinine), and a strong band of heparan sulfate was recognized on performing thin layer chromatography. HGSNAT enzyme activity in leukocytes was 0.7 nmol/17 hr/mg protein, which was significantly lower than the reference range (8.6-32 nmol/17 hr/mg protein). PCR and direct sequencing of the HGSNAT gene showed 2 mutations: c.234+1G>A (IVS2+1G>A) and c.1150C>T (p.Arg384*). To the best of our knowledge, this is the first case of MPS IIIC to be confirmed by clinical, biochemical, and molecular genetic findings in Korea.
Acetyltransferases/*genetics ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Child, Preschool ; Chromatography, Thin Layer ; Female ; Glycosaminoglycans/urine ; Heparitin Sulfate/chemistry/metabolism ; Humans ; Leukocytes/immunology/metabolism ; Mucopolysaccharidosis III/*diagnosis/genetics/radiography ; Mutation ; Republic of Korea ; Sequence Analysis, DNA

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.
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