OBJECTIVE: To analyze the characteristics of lysosomal enzymes in mucolipidosis (ML) type II α/β and type III α/β for the choice of enzyme evaluating indicators. METHODS: Multiple lysosomal enzymes including α-iduronidase (IDUA), α -N-acetylglucosaminidase (NAGLU), β-galactosidase-1 (GLB1), β-glucuronidase (GUSB), α-galactosidase A (GLA), glucocerebrosidase (GBA) and arylsulphatase A (ASA) in plasma and leukocyte of two Chinese pedigrees with ML type II α/β and type III α/β and healthy controls were determined. Previous publications on ML type II α/β and type III α/β during the last five years were retrieved from PubMed, CNKI and WanFang databases by using "mucolipidosis" as key word. RESULTS: The activities of several lysosomal enzymes were increased in the plasma of both patients: ASA, IDUA (20-fold) > GUSB (10-fold) > GLB1, GLA (5-fold) > NAGLU (2-fold), whilst there was no significant change in GBA. The activities of several lysosomal enzymes in the leukocyte of the two patients were normal. 15 lysosomal enzymes have been used in 22 previous studies, the most frequently used were hexosaminidase A and B (Hex A+B) (12 papers), α-mannosidase (α-man) (11 papers) and GUSB (10 papers). The degree of Hex A+B and α-man elevation was most obvious (24.4-fold and 24.7-fold on average respectively), followed by ASA (22.4-fold on average), GUSB is 18.8-fold on average. CONCLUSION Based on the lysosomal enzyme analysis of the two cases and literature review, ASA, GUSB, Hex A+B and α-man are recommended as the evaluating indicators for lysosomal enzyme analysis of ML type II α/β and type III α/β.
China ; Hexosaminidase A ; Humans ; Iduronidase ; Lysosomes ; Mucolipidoses/genetics* ; Pedigree

OBJECTIVE: To analyze the clinical and genetic characteristics of a child with mucopolysaccharidoses type I. METHODS: Enzymatic and genetic testing were carried out for the child who was admitted due to contraction of fingers and flexion deformity of lower limbs. The child was subjected to target exome capture sequencing. Candidate variants were verified by Sanger sequencing of the child, her parents and two sisters. RESULTS: The child had featured facial dysmorphism, short stature, round head, short neck, corneal turbidity and skeletal deformity. Enzyme test was positive, and genetic testing revealed that she had harbored c.1049delA (p.N350Mfs*4) and c.1815dupT (p.V606Cfs*53) compound heterozygous variants of the IDUA gene, which were inherited from her mother and father, respectively. Her two sisters had each carried one of above variants. c.1815dupT was known to be pathogenic, whilst c.1049delA was not reported in Human Gene Mutation Database. CONCLUSION The compound heterozygous variants of the IDUA gene probably underlay the disease in this child, among which the c.1049delA (p.N350Mfs*4) is unreported previously.
Child ; Dwarfism ; Female ; Genetic Testing ; Humans ; Iduronidase ; Mucopolysaccharidosis I ; Mutation ; Exome Sequencing

BACKGROUND: We developed an analytical method to measure alpha-L-iduronidase (IDUA) activity in dried blood spots. This was achieved by using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionization in the positive ion mode. METHODS: Chromatographic separation was completed using mobile phase involving water-formic acid and acetonitrile-formic acid over 2.8 min of run time on a column with a Kinetex XB-C18 (Phenomenex, USA). The detection of column effluent was performed using a Xevo TQ-S triple quadrupole mass spectrometer (Waters, USA) in the multiple-reaction monitoring mode. This method was verified with blank and control samples at four activity levels: base, low, medium, and high. Control materials were provided from Centers for Disease Control and Prevention (CDC). RESULTS: Intra- and inter-day precisions were between 2.6% and 16.5% and between 7.9% and 17.0%, respectively. A correlative regression study on the IDUA activity in CDC-control samples performed to assess the validity of the developed method showed a highly significant linear association (r2=0.9976) between the calculated and CDC-reported values and an obvious difference in activity among the four levels. This reliable analytical method was applied to mucopolysaccharidosis I (Hurler) screening of patients under treatment (n=4) and in normal controls (n=129). IDUA activity ranged from 8.98 to 77.12 micromol/hr/L) in normal controls, and patients undergoing medical treatment showed low IDUA activity. CONCLUSIONS: This method had advantages of simplicity, rapid sample preparation, and liquid chromatographic separation, which efficiently inhibited ionization suppression induced by matrix effects in mass spectrometric detection.
*Chromatography, High Pressure Liquid ; Dried Blood Spot Testing/*instrumentation ; Humans ; Iduronidase/*analysis/metabolism ; Mucopolysaccharidosis I/blood/*diagnosis ; Regression Analysis ; Substrate Specificity ; *Tandem Mass Spectrometry

OBJECTIVEMucopolysaccharidosis type I (MPS I; MIM# 252800) is an autosomal recessive disease that results from the deficiency in the lysosomal enzyme α-L-iduronidase(IDUA). IDUA is one of the enzymes involved in degradation of glycosaminoglycans heparan sulphate and dermatan sulphate. The deficiency of IDUA leads to widespread accumulation of partially degraded mucopolysaccharides inside lysosomes, resulting in progressive cellular and multiorgan dysfunction. Up to now there is no definitely effective treatment for this disorder, therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPSI families. This study was conducted to detect IDUA gene mutation in patients with MPSIand make a definite diagnosis of homozygote or heterozygote and make first trimester prenatal diagnosis.

METHODThe 2 male probands included in this study were diagnosed as MPSI patients in Peking Union Medical College Hospital, case 1 was 2 years old and case 2 was 5 years old. Genomic DNA was extracted from leucocytes in the 2 patients and 2 mothers' cultured amniocytes. IDUA gene DNA sequence was amplified by polymerase chain reaction (PCR) and the PCR products were sequenced directly. Novel mutations were analyzed in 100 normal chromosomes.

RESULTThe genotype of case 1 was p.L238R/c.883InsC, while of case 2 was c.531InsT/p.L346R. The fetal case 1 did not inherit the same pathogenic mutations as proband 1, the activity of the IDUA in amniocytes was 9.0 nmol/(h·mg pr). The fetal case 2 inherited the same pathogenic mutations with the proband, the genotype of fetal 2 was c.531InsT/p.L346R, the activity of the IDUA in amniocytes was 0.5 nmol/(h·mg pr).

CONCLUSIONOf the 4 mutations found in 2 MPS I patients, p. L238R, c.883InsC, c.531InsT were novel. The fetal case 1 was diagnosed as normal fetus while the fetus 2 was diagnosed as affected. The results of the two kinds of prenatal diagnostic methods were correspondent with each other.

Child, Preschool ; DNA Mutational Analysis ; Female ; Genotype ; Heterozygote ; Homozygote ; Humans ; Iduronidase ; genetics ; Male ; Mucopolysaccharidosis I ; diagnosis ; genetics ; Mutation ; Phenotype ; Pregnancy ; Prenatal Diagnosis

OBJECTIVETo explore the incidence of various types of mucopolysaccharidosis (MPS) and their clinical characteristics.

METHODSA total of 75 children highly suspected as having MPS underwent quantitative and electrophoretic analysis of urinary glycosaminoglycans (GAGs) and enzymatic analysis of seven types of MPS from January 2009 to December 2011. Fluorescence assay was used to measure the activities of α-L-iduronidase, iduronate-2-sulfatase, α-N-acetylglucosaminidase, galactosamine-6-sulfatase, β-galactosidase, arylsulfatase B and β-glucuronidase in the white blood cells.

RESULTSA total of 52 cases were confirmed with MPS based on clinical, radiological, and enzymatic examinations. The 52 cases, with a mean age of 4.0 ± 2.2 years, included 5 cases of MPS I (10%), 20 cases of MPS II (38%), 20 cases of MPS IVA (38%), 6 cases of MPS VI (12%) and 1 case of MPS VII (2%). No MPS IV B cases or MPS IIIB cases were found. Compared with healthy children of the same age, the GAG/Cr ratio was significantly elevated in 50 confirmed cases of MPS (two MPS IVA cases having no increased ratio). All children with increased urinary GAGs had a confirmed diagnosis of MPS. The age of onset was between 1 and 2 years after birth in most cases, and often complicated by hernia and valvular heart disease. Children with MPS I, MPS II, and MPS VI presented with ugly and unsmooth face, short stature, joint stiffness, and limitation of motion, while children with MPS IVA presented with short stature, skeletal dysplasia, and joint laxity.

CONCLUSIONSType IVA and type II are the most common in MPS cases, followed by type VI and type I. MPS children are characterized by special appearances including ugly and unsmooth facial appearance, short stature and skeletal dysplasia. Quantitative analysis of urinary GAG, as a simple, rapid, and reliable method, is recommended for screening of MPS.

Acetylglucosaminidase ; blood ; Child ; Child, Preschool ; Creatinine ; urine ; Female ; Glucuronidase ; blood ; Glycosaminoglycans ; urine ; Humans ; Iduronidase ; blood ; Infant ; Magnetic Resonance Imaging ; Male ; Mucopolysaccharidoses ; diagnosis ; enzymology ; pathology ; beta-Galactosidase ; blood

OBJECTIVETo investigate the molecular genetic mechanism of a Chinese patient with mucopolysaccharidosis type I (MPS I).

METHODSPCR-sequencing analysis was applied to detect the mutations in exons in alpha-L-iduronidase gene (IDUA) of the patient. Restriction fragment length polymorphism (RFLP) and allele-specific oligonucleotide hybridization (ASO) were used to confirm the identified mutations. PCR amplified DNA samples from 50 normal individuals were sequenced to demonstrate that the newly identified mutation was not polymorphism.

RESULTSThe patient was compound heterozygous for a previously reported nonsense mutation Q60X (178C > T) in exon 2, inherited from the mother, and a newly detected missense mutation D203N (607G > A) in exon 6 from the father. The newly identified mutation D203N was not found in PCR amplified products from 50 normal individuals, indicating that it was not polymorphism.

CONCLUSIONThe two identified mutations may be the cause resulting in patient's clinical phenotype.

Adolescent ; Base Sequence ; Codon, Nonsense ; DNA Mutational Analysis ; Exons ; genetics ; Female ; Humans ; Iduronidase ; genetics ; Male ; Mucopolysaccharidosis I ; genetics ; Mutation ; Mutation, Missense ; Pedigree ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Polymorphism, Restriction Fragment Length

OBJECTIVETo analyze mutations of IDUA gene in two pedigrees affected with mucopolysaccharidosis type I and provide prenatal diagnosis for them.

METHODSThe 14 exons of the IDUA gene were subjected to PCR amplification and Sanger sequencing.

RESULTSFor pedigree 1, the proband was found to harbor compound heterozygous mutations c.46-57delTCGCTCCTGGCC (p.Ser16_Ala19del) of exon 1 and c.1147delC (p.Arg383Alafs*57) of exon 8 of the IDUA gene, which were inherited from his father and mother, respectively. The latter was unreported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.46-57delTCGCTCCTGGCC mutation. For family 2, the proband was also found to carry compound mutations of the IDUA gene, namely c.721T to C (p.Cys241Arg) of exon 6 and c.1491delG (p.Thr497fs27) of exon 8, which were inherited from her mother and father, respectively. Neither mutation was reported previously. Prenatal diagnosis suggested that the fetus has carried a heterozygous c.721T to C mutation.

CONCLUSIONMutations of the IDUA gene probably underlie the MPS-I in both pedigrees. Above results have enriched the spectrum of IDUA gene mutations and facilitated prenatal diagnosis for both families.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; Child ; Child, Preschool ; China ; DNA Mutational Analysis ; Female ; Fetal Diseases ; diagnosis ; genetics ; Heterozygote ; Humans ; Iduronidase ; genetics ; Male ; Molecular Sequence Data ; Mucopolysaccharidosis I ; diagnosis ; embryology ; genetics ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Sequence Deletion

OBJECTIVEMucopolysaccharidosis type I (MPS I) is an autosomal recessive disease resulting from the deficiency in the lysosomal enzyme alpha-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS I H/S and MPS I S) patients with MPS I in northern China.

METHODSFourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS I patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted.

RESULTSSeven mutations were detected in the 11 MPS I patients, i.e., c.236 C to T (p. A79V), c.266 G to A (p.R89Q), c.265 C to T (p.R89W), c.532G to A (p.E178K), c.589G to A (p.G197S), c.1037T to G (p.L346R), and c.1877 G to A (p.W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i.e., p.A8, p.A20, p.H33Q, p.R105Q, p.A314, p. A361T, p.T388, p.T410 and p.V454I.

CONCLUSIONThe mutation spectrum of the IDUA gene in attenuated MPS I Chinese patients may be different from that in patients from other countries.

Adolescent ; Adult ; Base Sequence ; Child ; Child, Preschool ; China ; DNA Mutational Analysis ; methods ; Female ; Humans ; Iduronidase ; deficiency ; genetics ; Male ; Molecular Sequence Data ; Mucopolysaccharidosis I ; diagnosis ; enzymology ; genetics ; Mutation ; Polymerase Chain Reaction ; methods ; Polymorphism, Single Nucleotide ; Sequence Analysis, DNA ; methods ; Young Adult