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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	Li J, 2006(e)16701945
Citation	Li J., Wang Y., Zhou R., Wang B., Zhang H., Yang L. and Faraone S. V. (2006) "No association of attention-deficit/hyperactivity disorder with genes of the serotonergic pathway in Han Chinese subjects." Neurosci Lett, 403(1-2): 172-5.
Study Design	family-based
Study Type	Candidate-gene association study
Sample Size	HTR2A was successfully genotyped in a total of 311 trios. HTR5A was successfully genotyped in a total of 333 trios. HTR6 was successfully genotyped in a total of 298 trios.
Predominant Ethnicity	Mongoloid
Population	China
Age Group	Children/Adolescents

Detail Info

Summary	The current study examined five variants in three serotonin genes [those that code for serotonin receptors 2A (HTR2A), 5A (HTR5A) and 6 (HTR6)] in a relatively large sample of ADHD nuclear families. The transmission disequilibrium test (TDT) and the extended transmission disequilibrium test (ETDT) were performed to test for evidence of distorted transmission of alleles or haplotypes. No significant biased transmission was observed. These results do not support a substantial role of these serotonin gene in ADHD, however, additional work may be warranted before this association is definitively discounted.
Total Sample	Proband-parent ADHD trios were recruited from the child psychiatric clinics at Peking University Institute of Mental Health. HTR2A was successfully genotyped in a total of 311 trios. HTR5A was successfully genotyped in a total of 333 trios. HTR6 was successfully genotyped in a total of 298 trios.
Sample Collection	Han Chinese
Diagnosis Description	Proband-parent ADHD trios were recruited from the child psychiatric clinics at Peking University Institute of Mental Health. Affected individuals were diagnosed by at least two experienced clinicians according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for ADHD. Subjects were excluded if they showed evidence of bipolar affective disorder, childhood schizophrenia, autism, mental retardation or other neurological or complex medical illnesses.
Technique	Genomic DNA was extracted from blood using standard procedures. Both 102T>C and -1438A>G polymorphisms of the HTR2A gene and 267C>T of the HTR6 gene were genotyped according to protocols employed in previous studies. The same PCR reaction for -19G>C and 12A/T of the HTR5A gene was performed under the conditions described by Shimron- Abarbanell. Ten microlitres of PCR products were digested with BsaJI for more than 16 h, followed by BsrI for more than 16 h and then analyzed on polyacrylamide gel electrophoresis. Each gel was then immersed into water containing ethidium bromide for 30 min. Finally, products were analyzed with a Gel Doc 2000 imaging system (Bio-Rad, Hercules, CA) to detect and record the genotype of each sample.
Analysis Method	The transmission disequilibrium test (TDT) and the extended transmission disequilibrium test (ETDT) were performed to test for evidence of distorted transmission of alleles or haplotypes.
Result Description	No significant biased transmission was observed. These results do not support a substantial role of these serotonin gene in ADHD, however, additional work may be warranted before this association is definitively discounted.

Other variant reported by this study (count: 5)

Variant Name	Allele Change	Risk Allele	Statistical Values	Author Comments	Result of Statistical Analysis
HTR2A promoter 1438G/A	G/A		TDT P-value=0.428, McNemar X²=0.628 TDT P-value=0.428, McNemar X²=0.628	no biased transmission of any alleles was observed	Non-significant
HTR6 267C>T	C/T		TDT P-value=0.954, McNemar X²=0.003 TDT P-value=0.954, McNemar X²=0.003	no biased transmission of any alleles was observed	Non-significant
HTR5A 12A>T	A/T		TDT P-value=0.626, McNemar X²=0.238 TDT P-value=0.626, McNemar X²=0.238	no biased transmission of any alleles was observed	Non-significant
HTR5A -19G>C	G/C		TDT P-value=0.528, McNemar X²=0.399 TDT P-value=0.528, McNemar X²=0.399	no biased transmission of any alleles was observed	Non-significant
HTR2A T102C	C/T		TDT P-value=0.428, McNemar X²=0.628 TDT P-value=0.428, McNemar X²=0.628	no biased transmission of any alleles was observed	Non-significant

Genes reported by this study (count: 3)

Gene	Statistical Values/Author Comments	Result of Statistical Analysis
HTR6	no biased transmission of any alleles of 267C>T was observed...... no biased transmission of any alleles of 267C>T was observed More...	Non-significant
HTR5A	biased transmission of either alleles or specific haplotypes...... biased transmission of either alleles or specific haplotypes was not observed to probands More...	Non-significant
HTR2A	no biased transmission of any alleles of the 102T>C and -143...... no biased transmission of any alleles of the 102T>C and -1438A>G was observed More...	Non-significant