Shuan-Pei Lin

Mutation spectrum of MMACHC in Chinese patients with combined methylmalonic aciduria and homocystinuria.

The cblC type of combined methylmalonic aciduria (MMA) and homocystinuria (HC) is the most common inborn error of vitamin B12 metabolism and is caused by mutations in the MMACHC gene. To elucidate the spectrum of mutations that causes combined MMA and HC in Chinese patients, the MMACHC gene was sequenced in 79 unrelated Chinese patients. Sequence analysis identified 98.1% of disease alleles and found that all patients had at least one MMACHC mutation. A total of 24 mutations were identified. Out of the 24 mutations identified, 9 were novel ones, including missense mutations (c.365A>T and c.452A>G), nonsense mutations (c.315C>G and c.615C>A), deletions (c.99delA and c.277-3_c.303del30), duplications (c.248dupT and c.626dupT) and an insertion (c.445_446insA). The c.609G>A, c.658_660delAAG, c.482G>A, c.394C>T and c.80A>G mutations were the most common mutations and accounted for 80% of disease alleles. Haplotype analysis suggests that the spread of the c.80A>G, c.609G>A and c.658_660delAAG mutations in Chinese patients were caused by a founder effect. The results indicate that defects occurring in the MMACHC gene are the major cause of this disease in Chinese patients with combined MMA and HC, and direct mutation analysis can therefore be used as a rapid confirmatory diagnosis among these Chinese patients.

Characterization of pulmonary function impairments in patients with mucopolysaccharidoses--changes with age and treatment.

The mucopolysaccharidoses (MPS) comprise a group of inherited lysosomal storage disorders characterized by deficiencies in enzymes catalyzing the degradation of glycosaminoglycans. Impairment of pulmonary function is an important health problem for patients with MPS. However, there are few published reports on the prevalence and severity of pulmonary dysfunction in relation to age and treatment in this disorder.

Netherton syndrome: mutation analysis of two Taiwanese families

Netherton syndrome (NS) is a severe autosomal recessive skin disorder characterized by congenital ichthyosiform erythroderma, hair shaft abnormalities, and atopic diathesis. Recently, pathogenic mutations were identified in serine protease inhibitor Kazal-type 5 (SPINK5), the gene that encodes lympho-epithelial Kazal-type related inhibitor (LEKTI), a type of serine protease inhibitor involved in the regulation of skin barrier formation and immunity. In the present report, we describe the mutation analysis of two Taiwanese patients with NS. Patient 1 has heterozygous mutations; the maternal allele has novel T808I (C–T transition in codon 808) and the paternal allele has recurrent R790X (C–T transition in codon 790). Patient 2 is homozygous for a novel polymorphism R267Q (G–A transition in codon 267). The change was not detected in the patient’s father. Haplotype analysis revealed that the patient was homozygous for the 5 single nucleotide polymorphisms in the genomic sequence of SPINK5 as well as the flanking (GT)17 and D5S413, in addition to the discrepancy of R267Q. Nevertheless real-time quantitative PCR analysis revealed no microdeletion in the genomic sequence of SPINK5. Thus uniparental disomy of maternal SPINK5 allele was indicated.

Mutation identification and characterization of a Taiwanese patient with fucosidosis

AbstractFucosidosis is a rare lysosomal storage disease caused by a defect of the α-L-fucosidase (FUCA1) gene. Worldwide 26 mutations underlying the disease have been reported. By direct DNA sequencing of exons and flanking introns, homozygous Y126X mutation and Q281R polymorphism were found in a Taiwanese patient with fucosidosis. Upon expressing in COS-7 cells, 97.4% of α-L-fucosidase activity compared with that of the wild-type construct was observed in the cDNA containing Q281R polymorphism. Western blot analysis revealed a 58-kDa precursor and 56-kDa mature forms for cells transfected with wild-type and Q281R enzymes. Using the fluorogenic substrate, the Michaelis constants and maximal velocities of both enzymes were very similar. While no appreciable enzyme activity (0.0%) was observed with Y126X mutation, no apparent decrease in FUCA1 mRNA level was seen with Y126X mutation. The expressed truncated Y126X protein was unstable and largely degraded. The delineation of the molecular defect could serve to complement future prenatal diagnosis for this family when necessary.

Mutation Profile of the MUT Gene in Chinese Methylmalonic Aciduria Patients

The mut-type methylmalonic aciduria (MMA, MIM 251000) is caused by a deficiency of mitochondrial methylmalonyl-CoA mutase (MCM, E.C. 5.4.99.2) activity, which results from defects in the MUT gene. To elucidate the mutation spectrum of the MUT gene in Chinese MMA patients, 13 exons of the MUT gene, including untranslated regions, were analyzed by PCR-based sequencing for 42 unrelated Chinese MMA patients. All the 42 patients were found to have at least one MUT mutation. A total of 41 mutations were identified. Of these mutations, 20 were novel ones, including one nonsense mutation (c.103C>T), 12 missense mutations (c.316A>C, c.424A>G, c.494A>G, c.554C>T, c.599T>C, c.919T>C, c.1009T>C, c.1061C>T, c.1141G>A, c.1208G>A, c.1267G>A, and c.1295A>C), one duplication (c.755dupA), three small deletions (c.398_399delGA, c.1046_1058del, and c.1835delG), two mutations that might affect mRNA splicing (c.754-1G>A and c.1084-10A>G), and one major deletion. Among the mutations identified, the c.1280G>A (15.5%), c.729_730insTT (10.7%), c.1106G>A (4.8%), c.1630_1631GG>TA (4.8%), and c.2080C>T (4.8%) accounted for 40% of the diseased alleles. The c.1280G>A and c.729_730insTT mutations were found to be the most frequent mutations in Southern and Northern Chinese, respectively. The results of microsatellite analysis suggest that the spread of c.729_730insTT among the Northern Chinese and of c.1280G>A and c.1630_1631GG>TA among the Southern Chinese may have undergone founder effects. This mutation analysis of the gene responsible for mut-type MMA will help to provide a molecular diagnostic aid for differential diagnosis of MMA and could be applied for carrier detection and prenatal diagnosis among Chinese family at risk of mut-type MMA.

Clinical Features of Osteogenesis Imperfecta in Taiwan

BACKGROUND/PURPOSEnOsteogenesis imperfecta (OI) (MIM 166200, 166210, 259420 and 166220) is a congenital disorder characterized by increased bone fragility and low bone mass. Information regarding the clinical features of this genetic disorder is lacking in Taiwan. This study aimed to characterize the clinical features of OI patients in Taiwan to establish a practical correlation for distinguishing different clinical subtypes of the disorder.nnnMETHODSnA review of medical records identified 48 patients with OI (33 female and 15 male; age range, 2 months to 53 years) from January 1996 to June 2008. Diagnosis and classification, using the classification system outlined by Sillence et al, were based on clinical and radiological characteristics. We also analyzed the clinical presentation, physical examination and bone mineral density (BMD) among the different subtypes of OI.nnnRESULTSnRetrospective analysis of the medical records revealed that 48 OI patients could be classified into types I (n = 19), III (n = 10), and IV (n = 19). There were statistically significant differences between these three types in terms of height, weight, BMD, dentinogenesis imperfecta, bone deformity, scoliosis, walking ability, annual fracture rate, and family history. However, no significant differences were noted for blue sclera (p = 0.075) and hearing loss (p = 0.832).nnnCONCLUSIONnNine of the 11 clinical features examined---height, weight, BMD, dentinogenesis imperfecta, bone deformity, scoliosis, walking ability, fracture rate, and family history---were significantly different among the three types of OI patients. This finding may be of help in evaluating patients and establishing their prognosis.

Mucopolysaccharidosis I (Scheie syndrome): A rare cause of severe aortic stenosis in a 31-year-old man.

a Department of Medicine, Mackay Medical College, New Taipei City, Taiwan b Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan c Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan d Department of Early Infant Care and Education, Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan e Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan f Division of Cardiology, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan g Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan h Medical College, Fu-Jen Catholic University, Taipei, Taiwan

Assessment of body composition using bioelectrical impedance analysis in Prader-Willi syndrome

This study investigated the use of bioelectrical impedance analysis (BIA) as a means of assessing body composition in patients with Prader-Willi syndrome (PWS). Segmental, multifrequency BIA was performed on 30 patients with PWS (16 males and 14 females; mean age: 8.1xa0±xa03.9 years; age range: 2.9-19.6 years) using eight tactile electrodes. No patient had received growth hormone treatment prior to baseline measurements. Standard deviation scores for height, weight, and body mass index were -0.96xa0±xa01.29, 2.28xa0±xa02.66, and 3.14xa0±xa02.74, respectively. Percentages of body fat, total body water, and soft lean mass were 45.9xa0±xa010.8%, 36.6xa0±xa07.3%, and 49.9xa0±xa09.9%, respectively. Body fat percentage was positively correlated with the body mass index standard deviation score (rxa0=xa00.665, pxa0<xa00.01). Follow-up BIA was also performed on five patients who received growth hormone therapy (duration of treatment: 1.5-4.6 years). All of these patients showed reductions in their body fat percentages after treatment. BIA confirmed a significantly higher percentage of body fat in patients with PWS compared with normal children. These findings and the follow-up data can be used to develop quality care strategies for patients with PWS.

X-linked Myotubular Myopathy with a Novel MTM1 Mutation in a Taiwanese Child

We report a male, preterm newborn infant with X-linked myotubular myopathy, the most severe type of the disease. He presented at birth with generalized hypotonia, difficulty in swallowing, and respiratory distress with frequent episodes of atelectasis. The infant had a long thin face, generalized hypotonia, and arachnodactyly. Diagnosis was based on fetal history, muscle histopathology, electron microscopy and a genetic study. A base pair change was detected in exon 11 of the MTM1 gene: c.1160C>A, which caused an amino acid change, p.S387Y. The fathers gene was normal but the mother had the same mutation as her son and was thus a carrier.

AB108. The appliance of Bio-Plex immunoassay using dried blood spots for mucopolysaccharidosis IVA newborn screening in Taiwan—a pilot study

Background nMucopolysaccharidosis (MPS) IVA is an autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-6-sulfatase (GALNS) resulting in excessive lysosomal storage of keratan sulfate. This excessive storage causes a systemic skeletal dysplasia, short stature, and joint abnormalities. Treatments for MPS IVA are available. Better outcomes are associated with early treatment, which highlights a need for newborn screening for MPS IVA.