INTRODUCTIONThe nationwide neonatal screening for glucose-6-phosphate dehydrogenase (G6PD) deficiency in Taiwan was started on 1 July 1987. A network of G6PD referral hospitals distributed all around Taiwan was organised for follow-up, confirmatory testing, medical care and genetic counselling. To assess the reliability of confirmatory and screening tests, an external quality assurance (QA) programme for G6PD assay was developed.

MATERIALS AND METHODSLyophilised quality control (QC) materials and dried blood spots were prepared from erythrocytes and whole blood for confirmatory and screening tests, respectively. The external QA surveys were carried out every 1 to 2 months. The QA results were evaluated and compared to the consensus result and reference value. The test results were submitted through internet by participating laboratories and the summary reports were published on a webpage (http:// www.g6pd.tw) within 2 weeks.

RESULTSTwenty-one referral laboratories in Taiwan and 16 screening laboratories in Germany, Lebanon, Mainland China, Philippines, Thailand, Taiwan, Turkey, and Vietnam have been participating in the QA programme. From 1988 to 2007, 144 QA surveys for confirmatory testing were sent to referral laboratories. Among the 2,622 reports received, 292 (11.1%) were found to be abnormal. Interlaboratory coefficient of variation (CV) for the confirmatory test has reached below 10% in recent years. The significant improvement in interlaboratory CV was found to be correlated with the preventive site visits to the referral laboratories since November 2004. From 1999 to 2007, 52 external QA surveys for the screening test were performed. Among 504 reports received, 97 (19.2%) were found to be abnormal. From the 5040 blood spots tested by the screening laboratories, 95 false negative (1.9%) and 187 false positive (3.7%) results were reported.

CONCLUSIONSThe external QA programme has been useful for monitoring the performance of the referral hospitals and screening laboratories and helpful for the participating laboratories to improve their test quality.

Glucosephosphate Dehydrogenase Deficiency ; diagnosis ; Humans ; Infant, Newborn ; Neonatal Screening ; standards ; Quality Assurance, Health Care

OBJECTIVETo determine distribution and mutation pattern of type P ATP7B gene mutation and to explore genotype and phenotype correlation in patients with Wilson's disease (WD).

METHODSSixty patients with WD from 57 no kinship families, 37 male and 23 female, were enrolled in this study. The age of onset ranged from 4.6 - 39 years, < or = 16 years in 55 patients. Some exons of ATP7B gene mutation were analyzed in patients with WD by using biochemical methods, polymerase chain reaction-single strand configuration polymorphism (PCR-SSCP), restriction fragment and DNA sequence analysis. Totally 778 coding regions were identified with restriction enzyme Msp I. The activity of Cu-ATPase was assessed by measuring inorganic phosphorus in 3 patients with known genotype.

RESULTSFifty-two of 60 patients (86%) had presented with hepatic manifestations, 30 of them had only hepatic manifestations, 12/52 patients had hepatic and neurological manifestations at the same time; 10/52 patients had hepatic and other symptom; 7/60 patients had only neurological symptom, one patient had no symptom. Eleven mutations were detected by DNA sequencing, including five missense mutations (R778L, V1140A,G943S, V1106I and V1216M), one deletion (1384del17) and five polymorphisms (IVS4-5T/C, A2495G, C2310G, IVS18 + 6C/T and IVS20 + 5A/G) were identified. R778L mutation was identified 52/114 alleles (45.6%). R778L occurred in 38/52 patients with hepatic manifestation (73%), homozygosis of R778L was demonstrated in 14 patients and heterozygosity of R778L in 24 patients. V1106I mutation was 1.7%, G943S, V1140A, and V1216M was 0.86% respectively in this study. Two patients with delayed onset of neurological symptoms occurred V1106I mutation of ATP7B. Cu-ATPase activity of 3 patients with known mutation (R778L/V1106I, R778L/V1216M and R778L/R778L) declined by 44.55%, 88.23% and 69.49%, respectively, compared with normal control.

CONCLUSIONThe 1384del17bp and V1106I are two novel mutations found in patients with WD. R778L was common mutation of ATP7B gene with frequency of 45.6% in this study. The mutation in exon 8 of WD gene may play an important role in pathogenesis of WD in Chinese. Carriage of R778L mutation seems to be correlated with hepatic manifestation.

Adenosine Triphosphatases ; genetics ; Adolescent ; Adult ; Cation Transport Proteins ; genetics ; Child ; Child, Preschool ; Copper-transporting ATPases ; DNA Mutational Analysis ; Exons ; Female ; Gene Frequency ; Genotype ; Hepatolenticular Degeneration ; enzymology ; genetics ; pathology ; Humans ; Male ; Mutation ; Phenotype ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational ; Sequence Analysis, DNA