Further evidence for an association between mandibular height and the growth hormone receptor gene in a Japanese population.
BACKGROUND
Craniofacial morphology has a significant genetic component. It has recently been reported that single nucleotide polymorphisms (SNPs) in the growth hormone receptor gene (GHR) are associated with mandibular height. To confirm these findings, we genotyped SNPs in healthy Japanese subjects, about 1.7 times the number analyzed in previous reports.


METHODS
By using 5 SNPs in exon 10 of the GHR, we studied the relationships between genotypes and craniofacial linear measurements. The allelic frequencies in a multi-ethnic population (Han Chinese, African American, European American, and Hispanic) were also observed.


RESULTS
There was a significant association between SNPs and mandibular ramus height (P = 0.029), confirming our previous report of an association between polymorphism P561T and mandibular ramus height. Moreover, the SNP, C422F, was in linkage disequilibrium with P561T. Subjects with genotype CC of polymorphism P561T and genotype GG of polymorphism C422F had significantly greater mandibular ramus height than those with genotypes CA and GT. Four of the 5 SNPs were found almost exclusively in Asians, with the frequencies in other populations extremely small.


CONCLUSIONS
Our results indicate that the GHR polymorphisms P561T and C422F are associated with mandibular ramus height in Japanese population and suggest that the SNPs of the GHR associated with the Japanese are likely to be different in other ethnic groups. This might partly explain the differing craniofacial morphology among different ethnicities.
Tomoyasu
Yoko
Y
Department of Orthodontics, School of Dentistry, Showa University, Tokyo, Japan.
Yamaguchi
Tetsutaro
T
Tajima
Atsushi
A
Nakajima
Toshiaki
T
Inoue
Ituro
I
Maki
Koutaro
K
D000225:Adenine; D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000235:genetics; D044466:Asian People / Q000235:genetics; D002508:Cephalometry; D002681:China / Q000208:ethnology; D003545:Cysteine / Q000235:genetics; D003596:Cytosine; D005091:Exons / Q000235:genetics; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006147:Guanine; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D007564:Japan; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D008875:Middle Aged; D010649:Phenylalanine / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011392:Proline / Q000235:genetics; D011986:Receptors, Somatotropin / Q000235:genetics*; D013912:Threonine / Q000235:genetics; D013941:Thymine; D044465:White People / Q000235:genetics; D055815:Young Adult
D011986:Receptors, Somatotropin; D013912:Threonine; D010649:Phenylalanine; D006147:Guanine; D003596:Cytosine; D011392:Proline; D000225:Adenine; D003545:Cysteine; D013941:Thymine