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Large-scale studies

Data Summary

Published Variant
- SNP: 1391
- CNV: 398
- Others: 173
Published Gene: 359
Published Region: 128
Pathway by PBA: 8
Study: 361

Study Report

Basic Info

Reference	Tang G, 200111496362
Citation	Tang G., Ren D., Xin R., Qian Y., Wang D. and Jiang S. (2001) "Lack of association between the tryptophan hydroxylase gene A218C polymorphism and attention-deficit hyperactivity disorder in Chinese Han population." Am J Med Genet, 105(6): 485-8.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	69 nuclear families
Predominant Ethnicity	Mongoloid
Population	China
Gender	47 male, 22 female
Age Group	Children/Adolescents : average age: 10.3 (SD=0.78) years

Detail Info

Summary	In this study, they examined the relationship between the A218C polymorphism in TPH gene and ADHD. Sixty-nine ADHD patients and their biological parents were investigated. The A218C polymorphism in intron 7 of TPH gene was detected by PCR-RFLP method. No allele or genotype concerned with this A218C polymorphism was found to be associated with ADHD when analyzed with the haplotype relative risk method. Therefore, their data indicate that the TPH gene A218C polymorphism may not be a susceptibility factor of ADHD in the Chinese Han population.
Total Sample	Sixty-nine nuclear families participated in the present study. Among these ADHD children, 47 were male and 22 were female. The average age was 10.3 (SD=0.78) years and the average IQ was 97.8 (SD=15.97).
Sample Collection	Sixty-nine nuclear families participated in the present study. ADHD probands were recruited from the Hyperactivity, Attention, and Learning Problems (HALP) School in Shanghai.
Diagnosis Description	They were all interviewed by at least two different child psychiatrists with the aid of their biological parents and teachers. Ratings were made using DSM-III-R criteria and the Chinese classification of metal disorder (CCMD)-II rating scales.
Technique	Genomic DNA was extracted from peripheral lymphocytes. PCR amplification of the region containing the TPH gene A218C polymorphism was performed with the following pair of primers: forward primer, 5'- TTCAGATCCCTTCTTCTATACCCCAGA-3'; reverse primer, 5'-GGACATGACCTAAGAGTTCATGGCA-3'. Each variant of the TPH A218C polymorphism in ADHD children and their parents was determined based on the size of PCR product on the gel visualized by ultraviolet illumination. As Bellivier et al. [1998] creported, the uncut PCR product is 918 base pair (bp) long. After digestion, the A-variant was cut into two fragments of 860 bp and 58 bp, while the C-variant was cut into three fragments of 615 bp, 245 bp, and 58 bp (58 bp cannot be seen on the gel).
Analysis Method	Allelic and genotypic frequencies of the TPH gene A218C polymorphism in ADHD offspring and their parents were estimated by counting alleles. These were assessed for Hardy-Weinberg equilibrium using the chi-square test. Association analysis between ADHD and the TPH A218C polymorphic variants was performed using the haplotype-based haplotype relative risk (HHRR) test [Terwilliger and Ott, 1992]. A P value <0.05 was considered statistically significant.
Result Description	No allele or genotype concerned with this A218C polymorphism was found to be associated with ADHD when analyzed with the haplotype relative risk method. Therefore, their data indicate that the TPH gene A218C polymorphism may not be a susceptibility factor of ADHD in the Chinese Han population.

Other variant reported by this study (count: 1)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
TPH1 intron7 A218C	A/C		allelic HHRR P-value=0.82, OR=0.94, X²(1df)=0.054...... allelic HHRR P-value=0.82, OR=0.94, X²(1df)=0.0541 More...	did not reveal statistically significant differences in allele frequency distribution between transmitted and nontransmitted alleles	Non-significant

Genes reported by this study (count: 1)