Chiung-g Lin

Association of Cytotoxic T-Lymphocyte-Associated Protein 4 (CTLA4) Gene Polymorphisms with Autoimmune Thyroid Disease in Children and Adults: Case-Control Study.

Autoimmune thyroid disease (AITD), including Graves disease (GD) and Hashimoto disease (HD), is an organ-specific autoimmune disease with a strong genetic component. Although the cytotoxic T-lymphocyte-associated protein 4 (CTLA4) polymorphism has been reported to be associated with AITD in adults, few studies have focused on children. The aim of our study was to investigate whether the CTLA4 polymorphisms, including -318C/T (rs5742909), +49A/G (rs231775), and CT60 (rs3087243), were associated with GD and HD in Han Chinese adults and children. We studied 289 adult GD, 265 pediatric GD, 229 pediatric HD patients, and 1058 healthy controls and then compared genotype, allele, carrier, and haplotype frequencies between patients and controls. We found that CTLA4 SNPs +49A/G and CT60 were associated with GD in adults and children. Allele G of +49A/G was significantly associated with GD in adults (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.21–1.84; corrected P value [Pc] < 0.001) and children (OR, 1.42; 95% CI, 1.15–1.77; Pc = 0.002). Allele G of CT60 also significantly increased risk of GD in adults (OR, 1.63; 95% CI, 1.27–2.09; Pc < 0.001) and GD in children (OR, 1.58; 95% CI, 1.22–2.04; Pc < 0.001). Significant linkage disequilibrium was found between +49A/G and CT60 in GD and control subjects (D’ = 0.92). Our results showed that CTLA4 was associated with both GD and HD and played an equivalent role in both adult and pediatric GD in Han Chinese population.

New Phylogenetic Groups of Torque Teno Virus Identified in Eastern Taiwan Indigenes.

Torque teno virus (TTV) is a single-stranded DNA virus highly prevalent in the world. It has been detected in eastern Taiwan indigenes with a low prevalence of 11% by using N22 region of which known to underestimate TTV prevalence excessively. In order to clarify their realistic epidemiology, we re-analyzed TTV prevalence with UTR region. One hundred and forty serum samples from eastern Taiwanese indigenous population were collected and TTV DNA was detected in 133 (95%) samples. Direct sequencing revealed an extensive mix-infection of different TTV strains within the infected individual. Entire TTV open reading frame 1 was amplified and cloned from a TTV positive individual to distinguish mix-infected strains. Phylogenetic analysis showed eleven isolates were clustered into a monophyletic group that is distinct from all known groups. In addition, another our isolate was clustered with recently described Hebei-1 strain and formed an independent clade. Based on the distribution pattern of pairwise distances, both new clusters were placed at phylogenetic group level, designed as the 6th and 7th phylogenetic group. In present study, we showed a very high prevalence of TTV infection in eastern Taiwan indigenes and indentified new phylogenetic groups from the infected individual. Both intra- and inter-phylogenetic group mix-infections can be found from one healthy person. Our study has further broadened the field of human TTVs and proposed a robust criterion for classification of the major TTV phylogenetic groups.

The HLA-B gene and Hashimoto disease in Han Chinese children: a case-control and family-based study.

Hashimoto disease (HD) is an autoimmune thyroid disease resulting from complex interactions between genetic and environmental factors. The human leukocyte antigen (HLA) gene has been established to be involved in the susceptibility to HD. We aim to investigate the associations between HLA-B alleles and Han Chinese children with HD by both case-control and family-based studies. A total of 108 unrelated children with HD, 380 unrelated healthy controls, 58 trios of affected patients and their parents, and 75 trios of unaffected siblings and their parents were recruited. HLA-B genotyping was performed by polymerase chain reaction and detected with a sequence-specific oligonucleotide probes system. We found that B*46:01 allele (OR = 2.31, 95% CI 1.60-3.34, P(c) = 9.99 × 10(-5)) and carrier (OR = 3.28, 95% CI 2.10-5.11, P(c) = 1.35 × 10(-6)) were associated with HD risk. Transmission/disequilibrium test further confirmed an overtransmission of the B*46:01 (OR 2.55, 95% CI 1.36-6.10, P = 6.5 × 10(-3)). The findings were similar in females when stratified by gender. In conclusion, our results clearly identify that HLA-B*46:01 confers susceptibility to HD in Han Chinese children. Further studies with larger children cohort are required to confirm the role of B*46:01 in the development of HD.

The HLA-DRB1 gene and Graves disease in Taiwanese children: a case-control and family-based study

Graves disease (GD) is an autoimmune thyroid disease with a female preponderance and a wide range of ages at onset, and human leukocyte antigen (HLA) gene plays a primary role in the susceptibility to GD. We aim to investigate the associations between HLA-DRB1 alleles and Taiwanese children with GD by both case-control and family-based studies. A total of 241 unrelated children with GD, 539 healthy controls, 115 trios of affected patients and their parents, and 121 trios of unaffected siblings and their parents were recruited. HLA-DRB1 genotyping was performed by polymerase chain reaction and sequence-based typing assays. We found that DRB1*09:01 (OR=2.60, 95% CI 2.02-3.35, Pc=6.55×10(-13)) was associated with GD risk, while DRB1*12:02 (OR=0.32, 95% CI 0.20-0.53, Pc=4.55×10(-5)) was protective against GD. Transmission/disequilibrium test further confirmed an overtransmission of the DRB1*09:01 (OR 3.37, 95% CI 2.13-6.22, Pc=1.0×10(-5)) and an undertransmission of the DRB1*12:02 (OR 0.21, 95% CI 0.05-0.42, Pc=1.7×10(-3)). The findings were similar in females when stratified by gender. In conclusion, our results clearly identify that HLA-DRB1*09:01 confers susceptibility to GD and DRB1*12:02 exerts protection against GD development in Taiwanese children.

Improved Diabetic Control During Oral Sulfonylurea Treatment in Two Children with Permanent Neonatal Diabetes Mellitus

Permanent neonatal diabetes mellitus (PND), defined as diabetes diagnosed in the first 6 months of age and requiring life-long insulin therapy, is a rare disorder of unknown etiology. Activating mutations of the KCNJ11 gene, which encodes the Kir6.2 subunit of the ATP-dependent potassium channel in beta-cells, have been found to cause 30-58% of cases of PND. Sulfonylurea treatment in theses patients reduces or eliminates the need for exogenous insulin. We report two Taiwanese boys who were diagnosed with PND at 1 and 4.5 months of age. They had been treated with exogenous insulin for 6 and 15 years, respectively. In September 2006, they were both found to have a KCNJ11 mutation (valine-to-methionine at codon 59; V59M). Glibenclamide successfully increased the basal C-peptide level, lowered HbA(1c), and reduced blood sugar excursions. In one patient, the insulin dose was reduced to 0.2 U/kg/day, and the other was able to discontinue insulin altogether. These two cases from Taiwan add to the experience with similar mutations reported in Caucasians.

A new HLA-B*39 allele, HLA-B*39:01:15, discovered in a Taiwanese rheumatoid arthritis patient

The new allele B*39:01:15 differs from B*39:01:01 by a point mutation at position 315 (G>T) of exon 2.

Mutations in Pseudohypoparathyroidism 1a and Pseudopseudohypoparathyroidism in Ethnic Chinese

An inactivating mutation in the GNAS gene causes either pseudohypoparathyroidism 1a (PHP1A) when it is maternally inherited or pseudopseudohypoparathyroidism (PPHP) when it is paternally inherited. We investigated clinical manifestations and mutations of the GNAS gene in ethnic Chinese patients with PHP1A or PPHP. Seven patients from 5 families including 4 girls and 2 boys with PHP1A and 1 girl with PPHP were studied. All PHP1A patients had mental retardation. They were treated with calcitriol and CaCO3 with regular monitoring of serum Ca levels, urinary Ca/Cr ratios, and renal sonography. Among them, 5 patients also had primary hypothyroidism suggesting TSH resistance. One female patient had a renal stone which was treated with extracorporeal shockwave lithotripsy. She had an increased urinary Ca/Cr ratio of 0.481 mg/mg when the stone was detected. We detected mutations using PCR and sequencing as well as analysed a splice acceptor site mutation using RT-PCR, sequencing, and minigene construct. We detected 5 mutations: c.85C>T (Q29*), c.103C>T (Q35*), c.840-2A>G (R280Sfs*21), c.1027_1028delGA (D343*), and c.1174G>A (E392K). Mutations c.840-2A>G and c.1027_1028delGA were novel. The c.840-2A>G mutation at the splice acceptor site of intron 10 caused retention of intron 10 in the minigene construct but skipping of exon 11 in the peripheral blood cells. The latter was the most probable mechanism which caused a frameshift, changing Arg to Ser at residue 280 and invoking a premature termination of translation at codon 300 (R280Sfs*21). Five GNAS mutations in ethnic Chinese with PHP1A and PPHP were reported. Two of them were novel. Mutation c.840-2A>G destroyed a spice acceptor site and caused exon skipping. Regular monitoring and adjustment in therapy are mandatory to achieve optimal therapeutic effects and avoid nephrolithiasis in patients with PHP1A.

Investigation of cytotoxic T-lymphocyte-associated protein 4 gene polymorphisms in symptomatic gallstone disease

Gallstone disease (GSD), which is increasingly prevalent in Taiwan, develops through a complex process involving genetic, environmental, and immune factors. Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) limits T-cell proliferation. The present study looked for associations between symptomatic GSD and polymorphisms of the CTLA4 gene. For this case-control cross-sectional study among Taiwanese, 275 patients with symptomatic GSD and 852 controls were enrolled. Genotyping of CTLA4-318 C/T, +49 A/G, and CT60 A/G single nucleotide polymorphisms (SNPs) was performed by polymerase chain reaction-restriction fragment length polymorphism. The genotype, allele, carrier, and haplotype frequencies were calculated by direct counting or with Haploview 4.1 software. Genotype, allele, carrier, and haplotype frequencies of the CTLA4 SNPs studied were equally distributed in symptomatic GSD patients and controls. No significant associations between symptomatic GSD and these 3 SNPs were observed. Our data suggest that CTLA4-318 C/T, +49 A/G, and CT60 A/G SNPs do not confer increased susceptibility to symptomatic GSD.

Autoantibodies against islet cell antigens in children with type 1 diabetes mellitus

We investigated the prevalence of glutamic acid decarboxylase 65 autoantibody (GADA), insulinoma-associated protein 2 autoantibody (IA2A), and insulin autoantibody (IAA) in 750 children with type 1 diabetes (T1D) living in Taiwan. GADA, IA2A, and IAA were measured by radioimmunoassay. The data were assessed by χ2 test, binary logistic regression, and Spearman rank correlation. Of the 750 T1D patients, 66.3% had GADA, 65.3% IA2A, 35.7% IAA, and 17.2% no autoantibodies. The prevalence of GADA and IA2A significantly decreased along T1D duration. The positivity of either GADA or IA2A was 89.4% within the first year of disease and decreased to 36.7% after 9 years (P = 1.22 × 10–20). Female patients had significantly higher prevalence of GADA compared with male patients (72.3% vs. 59.7%, P = 0.00027). The patients diagnosed before 12 years of age had a positive rate of 92.2% for either GADA or IA2A. Patients diagnosed at age 12 or above had a significantly lower positive rate of 81.6% (P = 0.011). GADA and IA2A significantly correlated with each other (rs = 0.245, P = 1.09 × 10–11). We concluded that autoantibodies were detectable in 89.4% of T1D patients within one year after diagnosis. Their prevalence declined with disease duration. GADA was more prevalent in female patients. GADA and IA2A weakly correlated with each other.

Replication of results from a cervical cancer genome-wide association study in Taiwanese women

Genetic epidemiological studies show that genetic factors contribute significantly to cervical cancer carcinogenesis. Several genome-wide association studies (GWAS) have revealed novel genetic variants associated with cervical cancer susceptibility. We aim to replicate 4 GWAS-identified single nucleotide polymorphisms (SNPs), which were associated with invasive cervical cancer in Chinese women, in a Taiwanese population. The rs13117307 C/T, rs8067378 A/G, rs4282438 G/T, and rs9277952 A/G SNPs were genotyped in 507 women with cervical squamous cell carcinoma (CSCC) and 432 age/sex matched healthy controls by using TaqMan PCR Assay. Human papillomavirus (HPV) DNA test and typing were performed in CSCC patients. Only the rs4282438 SNP was found to be significantly associated (G allele, odds ratio [OR] = 0.67, P = 1.5 × 10−5). This protective association remained in HPV-16 positive CSCC subgroup (G allele, OR = 0.60, P = 1.2 × 10−5). In conclusion, our study confirms the association of rs4282438 SNP with CSCC in a Taiwanese population. However, larger sample sets of other ethnic groups are required to confirm these findings.