[Association between serotonin 2C gene polymorphisms and attention deficit hyperactivity disorder comorbid or not comorbid with learning disorder].
OBJECTIVE
To investigate the relationship between two HTR2C gene polymorphisms, that is C-759T and G-697C polymorphisms, and attention deficit hyperactivity disorder (ADHD) comorbid or not comorbid learning disorder (LD).


METHODS
Blood samples were taken from 189 trios with probands of ADHD comorbid LD (ADHD+LD) and 299 trios with probands of ADHD not comorbid LD (ADHD-LD). DNA was extracted and PCR was performed to amplify the fragments containing both C-759T and G-697C polymorphisms. Aci I was used to detect different alleles of the two polymorphisms. Allele- based and haplotype- based TDT analysis were used to test the association of the two polymorphisms of HTR2C gene and ADHD-LD and ADHD+LD.


RESULTS
-759C(chi(2)=6.961, P=0.008), -697G(chi(2)=8.346, P=0.004), as well as -759C/-697G haplotype were over- transmitted(chi(2)=9.000, P=0.002 7), while haplotype -759T/-697C was under- transmitted(chi(2)=7.784, P=0.005 3) to probands with ADHD-LD. No biased transmission of any allele and haplotype were found in families with probands of ADHD+LD.


CONCLUSIONS
ADHD-LD and ADHD+LD are different at the level of HTR2C gene polymrohisms of C-759T and G-697C. HTR2C is related to ADHD-LD, while not related to ADHD+LD.
Institute of Mental Health,Peking University, Beijing 10083, China.
Jun
J
Li
Yu-feng
YF
Wang
Ru-lun
RL
Zhou
Hao-bo
HB
Zhang
Bing
B
Wang
Li
L
Yang
D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000235:genetics* / Q000523:psychology; D002648:Child; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D007859:Learning Disabilities / Q000150:complications*; D015810:Linkage Disequilibrium; D008297:Male; D011110:Polymorphism, Genetic; D011569:Psychiatric Status Rating Scales; D044405:Receptor, Serotonin, 5-HT2C / Q000235:genetics*
D044405:Receptor, Serotonin, 5-HT2C