Comparing Strategies for Critical Congenital Heart Disease Newborn Screening.

OBJECTIVES: An extended newborn critical congenital heart disease (CCHD) screening program using oximetry has been implemented in Taipei, Taiwan since April 2014. This study was conducted to investigate the test accuracy and efficiency of this screening protocol. METHODS: This study analyzed data from 30 birthing facilities representing 87.9% of live births in Taipei. Positive screening was defined as oxygen saturation <95% in either extremity or a preductal-postductal oxygen saturation difference of >3%. This study cohort was used to retrospectively estimate outcomes on the basis of different CCHD screening protocols. RESULTS: During the study period, 93 058 of 94 204 (98.8%) infants who had no prenatal suspicion were screened. The referral rate was 0.17% (156/93 058), and up to 90% of test-positive infants were referred within 48 hours of life. Forty-two CCHD cases without prenatal suspicion were detected and 97.6% were diagnosed within 72 hours of life. Of the screened newborns, 4 CCHD cases passed the screening. The false positive and false negative rates were 0.12% and 0.04%, respectively. In addition, applying our database to Spanish and updated American Academy of Pediatrics screening strategies led to more CCHD case detection. CONCLUSIONS: The Taipei protocol provided an efficient and effective screening referral system in a community setting. For optimal efficiency, we advocated the updated American Academy of Pediatrics algorithm/Spanish recommendation with a modification of immediate referral if oxygen saturation ≤90% in either extremity. The updated protocol would be practicable for nationwide screening in Taiwan and could also be applied to other regions with similar medical care systems.

Long-term neurodevelopmental outcomes of significant neonatal jaundice in Taiwan from 2000-2003: a nationwide, population-based cohort study.

Newborns with significant neonatal jaundice (SNJ) would admit for evaluation and/or intervention due to an earlier or more rapid increase in bilirubin level. Bilirubin-induced neurological dysfunction in this population might be underestimated. We aimed to investigate the risk of long-term neurodevelopmental sequelae of SNJ in Taiwan. An SNJ 2000-2003 follow-up cohort consisting of 66,983 neonates was extracted from the nationwide, population-based health insurance database in Taiwan to survey the accumulative incidence of long-term (7-year) neurodevelopmental sequelae in comparison to a reference general-population neonate cohort of 12,579 individuals born in 2000. The SNJ follow-up cohort was furtherly categorized into subgroups according to interventions (phototherapy, intensive phototherapy, and exchange transfusion). The SNJ follow-up cohort exhibited significantly higher cumulative rates of long-term neurodevelopmental sequelae than did the reference cohort (P < 0.05). The risks of infantile cerebral palsy, hearing loss, and developmental delay in the SNJ follow-up cohort were between twice and three times of those in the reference cohort after adjusting for gender, comorbid perinatal disorders and urbanization levels. All intervention subgroups demonstrated higher risks for long-term neurodevelopmental sequelae than the reference cohort (P < 0.05) after adjustment. Patients with SNJ are at risk of developing neurodevelopmental disorders during their growth period. A scheduled follow-up protocol of physical and neurodevelopmental assessment during early childhood for these SNJ patients would potentially be helpful for the early detection of and intervention for neurodevelopmental disorders.

Outcomes of neonatal jaundice in Taiwan.

OBJECTIVE: To investigate the burden of clinically significant neonatal jaundice (SNJ) in Taiwan, 2000-2010. STUDY DESIGN: The nationwide, population-based health insurance database in Taiwan was used to investigate the incidence, kernicterus rate and mortality rates of SNJ cohort born between 2000 and 2010. RESULTS: From 2000 to 2010, up to 242 546 patients admitted with neonatal jaundice (NJ) were identified. The incidence of SNJ was 5.9% in 2000 and increased to 13.7% in 2010 (P<0.001). The mortality rate significantly decreased from 0.51% in 2000 to 0.26% in 2010 (P<0.001) and the average incidence of kernicterus was 0.86 per 100 000 live births, indicating dramatically decreased rates compared with earlier rates in Taiwan. CONCLUSIONS: In spite of the increased incidence rates, the rates of mortality and kernicterus in patients with NJ significantly declined in Taiwan. The public health prevention programme, clinicians' awareness and effective management might contribute to the reduction of these acute severe sequelae.

Development of a Newborn Screening Program for Critical Congenital Heart Disease (CCHD) in Taipei.

BACKGROUND: Early detection of critical congenital heart disease (CCHD) can significantly reduce morbidity and mortality among newborns. We investigate the feasibility of implementing a community-based newborn CCHD screening program in Taipei. METHODS: Twelve birthing facilities in Taipei participated in a trial screening program between October 1, 2013, and March 31, 2014. Newborns underwent pulse oximetry at 24-36 h old, with probes attached to the right hand and one lower limb. Any screening saturation ≥95% in either extremity, with an absolute difference of ≤3% between the right hand and foot, was accepted as a screening pass. A screening result was considered as a fail if the oxygen saturation was <95% at either probe site, on 3 separate occasions, each separated by 30 min or the first result was <95% at either probe site, and any subsequent oxygen saturation measurement was <90%. Public health nurses would follow up all missed or refused cases. RESULTS: Of the 6,387 live births, 6,296 newborns (coverage rate: 6,296/6,387 = 98.6%) underwent appropriate pulse oximetry screening. Sixteen newborns (0.25%) were reported to have a failed screening result. Five of these screen positive newborns were confirmed with CCHD; two of them were diagnosed solely attributed to the failed screening results. The false-positive rate was 0.18%. Implementing a 6-month screening program for CCHD produced good case detection rate, while using efficient screening and referral systems. CONCLUSION: This program was successful in integrating screening, referral and public health tracking systems. The protocol outlined in this report could provide a community-based model for worldwide implementation.

The mutation spectrum of the phenylalanine hydroxylase (PAH) gene and associated haplotypes reveal ethnic heterogeneity in the Taiwanese population.

Phenylalanine hydroxylase (PAH) deficiency is responsible for most cases of phenylketonuria (PKU). In this study of the PAH mutation spectrum in the Taiwanese population, 139 alleles were identified including 34 different mutations. The V190G, Q267R and F392I mutations are first reported in this study. The most common mutations, R241C, R408Q and Ex6-96A>G, account for 23.2%, 12.0% and 9.2%, of the mutant alleles, respectively. Haplotype analysis shows that R241C and Ex6-96A>G are exclusively associated with haplotype 4.3 to suggest founder effects. On the other hand, R408Q is found on two distinct haplotypes suggesting recurrent mutations. The spectrum of PAH mutations in Taiwan shows various links to those of other Asian regions, yet remarkable differences exist. Notably, R408Q, E286K and -4173_-407del, accounting for 21% of all mutant alleles in Taiwan, are very rare or are undetected among PKU cohorts of other Asian regions to suggest local founder effects. Moreover, the low homozygosity value of 0.092 hints at a high degree of ethnic heterogeneity within the Taiwanese population. Our study of PAH mutation spectrum and the associated haplotypes is useful for subsequent study on the origin and migration pattern via Taiwan, an island at the historical crossroad of migration of ancient populations.

The universal newborn hearing screening program of Taipei City.

OBJECTIVES: To establish a hearing screening program with high coverage, low referral rate, high follow-up rate, and early intervention in Taipei City. METHODS: From September 2009 to December 2010, 85% delivery units in Taipei City, which includes 20 hospitals and 14 obstetrics clinics, were recruited into the screening program in two stages. A total of 15,930 babies were born in these participating hospitals and clinics during the program period. Among these neonates, 15,790 underwent hearing screening test with automatic auditory brainstem response (AABR). The screening was free of charge to the parents. The hearing screening examination was performed 24-36 h after birth. The same test was repeated between 36 and 60 h of age if the baby failed the first hearing test. The neonate was referred to the diagnostic hospitals for further investigations if he failed the second test. RESULTS: The screening coverage rate was 99.1% (15,790/15,930). The incidence of bilateral moderate to severe and unilateral hearing loss was 1.4 per 1000 (22/15,790) and 1.5 per 1000 (24/15,790), respectively. Four percent (626/15,790) of newborns failed to pass the initial screening test and 1.0% of newborns failed to pass the second screening test. Therefore, 1.0% newborns were referred for diagnostic assessments. The follow-up rate was 94.4% (151/160). Sixty-four percent (14/22) of babies with bilateral hearing loss completed the full diagnostic hearing tests within 3 months of birth. CONCLUSIONS: The universal newborn hearing screening program is an adequate program for Taipei City with high coverage, low referral rate, and good follow-up rate. Screening fees covered by third parties, two-stage screening steps with AABR strategy, and the stringent monitoring system proved to be effective. LEVEL OF EVIDENCE: 2b, individual cohort study.

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.

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 B(12) 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.

Nationwide survey of extended newborn screening by tandem mass spectrometry in Taiwan.

In Taiwan, during the period March 2000 to June 2009, 1,495,132 neonates were screened for phenylketonuria (PKU) and homocystinuria (HCU), and 1,321,123 neonates were screened for maple syrup urine disease (MSUD), methylmalonic academia (MMA), medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) deficiency, isovaleric academia (IVA), and glutaric aciduria type 1 (GA-1) using tandem mass spectrometry (MS/MS). In a pilot study, 592,717 neonates were screened for citrullinemia, 3-methylcrotonyl-CoA carboxylase deficiency (3-MCC) and other fatty acid oxidation defects in the MS/MS newborn screening. A total of 170 newborns and four mothers were confirmed to have inborn errors of metabolism. The overall incidence was approximately 1/5,882 (1/6,219 without mothers). The most common inborn errors were defects of phenylalanine metabolism [five classic PKU, 20 mild PKU, 40 mild hyperphenylalaninemia (HPA), and 13 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency]. MSUD was the second most common amino acidopathy and, significantly, most MSUD patients (10/13) belonged to the Austronesian aboriginal tribes of southern Taiwan. The most frequently detected among organic acid disorders was 3-MCC deficiency (14 newborns and four mothers). GA-1 and MMA were the second most common organic acid disorders (13 and 13 newborns, respectively). In fatty acid disorders, five carnitine transport defect (CTD), five short-chain acyl-CoA dehydrogenase deficiency (SCAD), and two medium-chain acyl-CoA dehydrogenase (MCAD) deficiency were confirmed. This is the largest case of MS/MS newborn screening in an East-Asian population to date. We hereby report the incidences and outcomes of metabolic inborn error diseases found in our nationwide MS/MS newborn screening program.

External quality assurance programme for newborn screening of glucose-6-phosphate dehydrogenase deficiency.

INTRODUCTION: The 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 METHODS: Lyophilised 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. RESULTS: Twenty-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. CONCLUSIONS: The 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.

Frequency and distribution in East Asia of 12 mutations identified in the SLC25A13 gene of Japanese patients with citrin deficiency.

Deficiency of citrin, a liver-type mitochondrial aspartate-glutamate carrier (AGC), encoded by the SLC25A13 gene on chromosome 7q21.3, causes autosomal recessive disorders: adult-onset type II citrullinemia (CTLN2) and neonatal hepatitis associated with intrahepatic cholestasis (NICCD). So far, we have described 12 SLC25A13 mutations: 11 were from Japan and one from Israel. Three mutations found in Chinese and Vietnamese patients were the same as those in Japanese patients. In the present study, we identified a novel mutation IVS6+1G>C in a Japanese CTLN2 patient and widely screened 12 SLC25A13 mutations found in Japanese patients in control individuals from East Asia to confirm our preliminary results that the carrier frequency was high in Asian populations. Mutations 851-854del and 1638-1660dup were found in all Asian countries tested, and 851-854del associated with 290-haplotype in microsatellite marker D7S1812 was especially frequent. Other mutations frequently detected were IVS11+1G>A in Japanese and Korean, S225X in Japanese, and IVS6+5G>A in Chinese populations. We found a remarkable difference in carrier rates in China (including Taiwan) between north (1/940) and south (1/48) of the Yangtze River. We detected many carriers in Chinese (64/4169 = 1/65), Japanese (20/1372 = 1/69) and Korean (22/2455 = 1/112) populations, suggesting that over 80,000 East Asians are homozygotes with two mutated SLC25A13 alleles.

Quality assurance program for neonatal screening of glucose-6-phosphate dehydrogenase deficiency.

The nationwide neonatal screening of glucose-6-phosphate dehydrogenase (G6PD) deficiency in Taiwan was started on July 1, 1987. The effective collection rate has reached more than 96% of all newborns since 1993 and the overall incidence rate of G6PD deficiency was about 2%. This screening program has 3 screening centers and 18 referral hospitals, distributed around Taiwan including outlying islands. To assess the reliability of the confirmatory and screening tests, an external quality assurance (QA) program for G6PD assay was developed. For quantitative assay of G6PD activity, lyophilized quality control materials with different G6PD activities were prepared from red blood cells. For G6PD screening, quality control materials with different G6PD activities were prepared from whole blood and spotted onto the blood collecting filter paper. Periodically (1-2 months), the QC materials were sent to each of the referral hospitals and screening centers by speed post delivery. The external QA results were evaluated and compared to the median of all the reports and the reference values determined by our laboratory. Whenever an analytical system error was detected in any participating laboratory, troubleshooting was carried out either by contacting by phone or visiting in person. Twenty-one referral laboratories and 8 screening centers (3 in Taiwan, 2 in Mainland China, and one each in the Philippines, Thailand and Lebanon) participated in the QA program. Three to 5 QC specimens were sent to every participating referral laboratory for each quantitative survey. From January 1988 to June 2001, 104 QA surveys were carried out and 1,891 reports were received. Two hundred and thirty-nine (12.6%, 239/1,891) QA reports had abnormal results, attributed to clerical (13%, 31/239), experimental (17.2%, 41/239), and instrumental errors (46.4%, 111/239). Most of the experimental and instrumental errors were found in those laboratories that did not execute internal QA properly. For the screening QA program, 10 QC blood spots were delivered to every participating screening center for each survey. From March 1999 to June 2001, 15 screening surveys were performed with 111 reports received. One false negative (1/1,110) and 14 (14/1,110) false positive results were found in four (3.6%, 4/111) of the screening QA reports. The external quality assurance program proved useful for monitoring the performance of G6PD tests in referral hospitals and screening centers, and provided guidance for correcting analytical errors.