Most patients with isolated methylmalonic acidemia (MMA) /propionic acidemia (PA) presenting during the neonatal period with acute metabolic distress are at risk for death and significant neurodevelopmental disability. The nationwide newborn screening for MMA/PA has been in place in Taiwan from January, 2000 and data was collected until December, 2016. During the study period, 3,155,263 newborns were screened. The overall incidence of MMA mutase type cases was 1/121,356 (n = 26), 1 cobalamin B was detected and that for PA cases (n = 4) was 1/788,816. The time of referral is 8.8 days for MMA patients, and 7.5 days for PA patients. The MMA mutase type patients have higher AST, ALT, and NH3 values as well as a lower pH value (p < 0.05). The mean age for liver transplantation (LT) is 402 days (range from 0.6–6.7 yr) with 16 out of 20 cases (80.0%) using living donors. The mean admission length shortened from 90.6 days/year (pre-LT) to 5.3 days/year (at 3rd year post-LT) (p < 0.0005). Similarly, the tube feeding ratio decreased from 67.8 to 0.50% (p < 0.00005). The anxiety level of the caregiver was reduced from 33.4 to 27.2 after LT (p = 0.001) and the DQ/IQ performance of the patients was improved after LT from 50 to 60.1 (p = 0.07). MMA/PA patients with LT do survive and have reduced admission time, reduced tube feeding and the caregiver is less anxious.

Mucopolysaccharidosis type II (MPS II) is an X-linked recessive, multisystemic lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase. MPS II has a variable age of onset and variable rate of progression. In Asian countries, there is a relatively higher incidence of MPS II compared to other types of MPS. A retrospective analysis was carried out of 34 Taiwanese MPS II patients who died between 1995 and 2012. The clinical characteristics, medical records, age at death, and cause of death were evaluated to better understand the natural progression of this disease. The mean age at death of 31 of the patients with a severe form of the disease with significant cognitive impairment was 13.2 ± 3.2 years, compared with 22.6 ± 4.3 years in the three patients with a mild form of the disease without cognitive involvement (n = 2) or the intermediate form (n = 1) (p < 0.001). The mean ages at onset of symptoms and confirmed diagnosis were 2.5 ± 2.1 and 4.8 ± 3.1 years, respectively (n = 32). Respiratory failure was the leading cause of death (56 %), followed by cardiac failure (18 %), post-traumatic organ failure (3 %), and infection (sepsis) (3 %) (n = 27). Age at onset of symptoms was positively correlated with life expectancy (p < 0.01). Longevity gradually increased over time from 1995 to 2012 (p < 0.05). Respiratory failure and cardiac failure were the two major causes of death in these patients. The life expectancy of Taiwanese MPS II patients has improved in recent decade.

Information regarding the long-term outcome of enzyme replacement therapy (ERT) with recombinant human N-acetylgalactosamine 4-sulfatase (rhASB, galsulfase, Naglazyme®, BioMarin Pharmaceutical Inc.) for Taiwanese patients with mucopolysaccharidosis (MPS) VI is limited. Nine Taiwanese patients with MPS VI (4 males and 5 females; age range, 1.4 to 21.1 years) treated with weekly intravenous infusions of galsulfase (1.0 mg/kg) in 5 medical centers in Taiwan were reviewed. A set of biochemical and clinical assessments were evaluated annually. After 6.2 to 11.2 years of galsulfase treatment, 6 patients experienced improvement over baseline in the 6-minute walk test by a mean of 150 m (59% change over time), and 3 patients also increased the 3-minute stair climb test by a mean of 60 steps (46%). In a manual dexterity test, 3 patients decreased the time required to pick up 10 coins and put the coins into a cup by 15 s (33%). Shoulder range of motion in all 9 patients improved, and Joint Pain and Stiffness Questionnaire scores improved by 0.42 points (21%). Four patients showed improved pulmonary function. Five patients had positive effects on cardiac-wall diameters. Four patients had improved cardiac diastolic function. Liver and spleen sizes as measured by abdominal ultrasonography remained the same or decreased in all 9 patients. However, the severity degree of valvular stenosis or regurgitation did not show improvement despite ERT. A mean overall 69% decrease in urinary glycosaminoglycan (GAG) excretion indicated a satisfactory biomarker response. Long-term ERT was beneficial and safe for Taiwanese patients with MPS VI. This treatment reduced urinary GAG and had positive effects on a wide range of clinical functional assessments including endurance, mobility, joint function, pulmonary function, liver and spleen size, cardiac hypertrophy and diastolic dysfunction.

Hunter syndrome (mucopolysaccharidosis II; MPS II) is caused by a defect of the iduronate-2-sulfatase (IDS) gene. Few studies have reported integrated mutation data of Taiwanese MPS II phenotypes. In this study, we summarized genotype and phenotype correlations of confirmed MPS II patients and asymptomatic MPS II infants in Taiwan. Regular polymerase chain reaction and DNA sequencing were used to identify genetic abnormalities of 191 cases, including 51 unrelated patients with confirmed MPS II and 140 asymptomatic infants. IDS activity was analyzed in individual novel IDS variants using in vitro expression studies. Nineteen novel mutations were identified, in which the percentages of IDS activity of the novel missense mutations c.137A>C, c.311A>T, c.454A>C, c.797C>G, c.817C>T, c.998C>T, c.1106C>G, c.1400C>T, c.1402C>T, and c.1403G>A were significantly decreased (p < 0.001), c.254C>T and c.1025A>G were moderately decreased (p < 0.01), and c.851C>T was slightly decreased (p < 0.05) comparing with normal enzyme activity. The activities of the other six missense mutations were reduced but were insignificant. The results of genomic studies and their phenotypes were highly correlated. A greater understanding of the positive correlations may help to prevent the irreversible manifestations of Hunter syndrome, particularly in infants suspected of having asymptomatic MPS II. In addition, urinary glycosaminoglycan assay is important to diagnose Hunter syndrome since gene mutations are not definitive (could be non-pathogenic).