Ryuichi Hoshi

Genetic risk factors for nonsyndromic cleft lip with or without cleft palate in a Brazilian population with high African ancestry

Nonsyndromic cleft lip with or without cleft palate (NSCL ± P) is the most common orofacial birth defect, exhibiting variable prevalence around the world, often attributed to ethnic and environmental differences. Linkage analyses and genome‐wide association studies have identified several genomic susceptibility regions for NSCL ± P, mostly in European‐derived or Asian populations. Genetic predisposition to NSCL ± P is ethnicity‐dependent, and the genetic basis of susceptibility to NSCL ± P likely varies among populations. The population of Brazil is highly admixed, with highly variable ancestry; thus, the genetic determinants of NSCL ± P susceptibility may be quite different. This study tested association of 8 single‐nucleotide polymorphisms (SNPs), previously identified by genome‐wide studies in other populations, with NSCL ± P in a Brazilian population with high African ancestry. SNPs rs560426, rs642961, rs1530300, rs987525, rs3758249, rs7078160, rs17085106, and rs13041247 were genotyped in 293 Brazilian patients with NSCL ± P and 352 unaffected Brazilian controls. Each sample was also genotyped for 40 biallelic short insertion/deletion polymorphic markers to characterize genetic ancestry. The average African ancestry background was 31.1% for the NSCL ± P group and 36.7% for the control group. After adjustment for ancestry and multiple testing, the minor alleles of rs3758249 (OR: 1.58, 95% CI: 1.25–2.01, P = 0.0001) and rs7078160 (OR: 1.59, 95% CI: 1.21–2.07, P = 0.0002) were significantly associated with risk of NSCL ± P. Polymorphisms located in IRF6 (rs642961) and 8q24 (rs1530300 and rs987525) showed marginal associations in this Brazilian population with high African ancestry. These results indicate that rs3758249 at 9q22 and rs7078160 at 10q25.3 represent risk loci for NSCL ± P in the Brazilian population with high African ancestry.

Dental Anomalies in a Brazilian Cleft Population

Objective The aim of this study was to radiographically investigate the prevalence of dental anomalies outside the cleft area in a group of Brazilian patients with nonsyndromic cleft lip and/or palate (NSCL/P). Design, Participants, and Setting A retrospective analysis of 207 panoramic radiographs of patients with NSCL/P aged 12 to 45 years without history of tooth extraction and orthodontic treatment was performed. Results Dental anomalies were found in 75.4% of the patients, and tooth agenesis (29.2%) and supernumerary tooth (2.6%) were the most common anomalies. The risk of agenesis was higher among the individuals with cleft palate (CP) compared with individuals with cleft lip (CL) and cleft lip and palate (CLP) (agenesis: CP versus CL: odds ratio 6.27, 95% confidence interval 2.21-17.8, P = .0003; CP versus CLP: odds ratio 2.94; 95% confidence interval 1.27-6.81, P = .01). The frequency of dental agenesis was higher in patients with unilateral complete CLP (agenesis: P < .0001), incomplete bilateral CLP (agenesis: P = .0013), complete CP (agenesis: P < .0001), and incomplete CP (agenesis: P < .0001). The frequency of supernumerary teeth was higher in patients with bilateral complete CLP (P < .0001). The frequency of dental agenesis (P < .0001) and ectopic tooth (P = .009) was higher than the frequency estimated for general population. Conclusions The prevalence of dental anomalies in patients with NSCL/P was higher than that reported in overall population. This study found preferential associations between dental anomalies and specific extensions of NSCL/P, suggesting that dental agenesis and ectopic tooth may be part of oral cleft subphenotypes.

Characterization of Susceptibility Polymorphisms For Nonsyndromic Cleft Lip With or Without Cleft Palate

Fissuras do labio ou palato nao sindromicas (FL/PNS) sao as anomalias congenitas craniofaciais mais comuns, com prevalencia de 1:500-2.500 nascidos vivos. Possuem etiologia complexa, com participacao de fatores ambientais e geneticos. Estudos de larga escala genomica (GWAS) descreveram varias regioes cromossomicas e genes candidatos a etiologia das FL/PNS, entretanto poucos foram confirmados em diversas populacoes, o que pode ser resultado da diferenca na composicao etnica das populacoes. Recentemente, GWAS realizados com populacoes da Europa e da Asia identificaram polimorfismos de suscetibilidade para FL/PNS nos genes FGF12, VCL, CX43, e nos loci 1p36, 2p21, 3p11.1, 8q21.3, 10q25, 13q31.1, 15q22.2 e 17q22. Como o Brasil e composto por uma populacao miscigenada, torna-se importante confirmar se esses marcadores tambem mostram suscetibilidade a FL/PNS na populacao brasileira. O objetivo deste estudo foi avaliar o envolvimento de polimorfismos geneticos que foram descritos como marcadores de risco para o desenvolvimento de FL/PNS em pacientes brasileiros com FL/PNS. Este estudo caso-controle, com uma analise estruturada de acordo com as proporcoes de ancestralidade de cada individuo, avaliou 16 marcadores polimorficos de suscetibilidade as fissuras orais em 300 pacientes com FL/PNS e 395 individuos sem fissura provenientes de Minas Gerais, Brasil e 7 marcadores polimorficos em 505 pacientes com FL/PNS e 594 individuos sem fissura, provenientes de Minas Gerais e Bahia, Brasil. Os polimorfismos foram genotipados pelo metodo de discriminacao alelica com sondas fluorescentes. A ancestralidade genomica de cada individuo foi determinada pela caracterizacao de 40 marcadores bialelicos de insercao/delecao (INDELs). A distribuicao genotipica de todos os polimorfismos no grupo controle respeitou o equilibrio de Hardy-Weinberg, exceto para o polimorfimo rs7632427 que foi excluido da analise. Foram observadas associacoes entre os polimorfismos rs227731, rs742071, rs1873147, rs8001641 e rs7590268 e de um haplotipo formado pelos polimorfismos rs10787760, rs6585429 e rs1871345 do gene VAX1 com FL/PNS. Apos a correcao de Bonferroni para multiplos testes, foram observadas associacoes significativas com os polimorfismos rs742071, rs1873147 e rs227731. Entretanto, a frequencia dos alelos de risco variou entre as regioes geograficas, de acordo com as proporcoes de ancestralidade europeia e africana. O grupo com maior proporcao de marcadores de origem europeia mostrou associacao com rs227731, enquanto que o grupo com proporcao maior de marcadores de origem africana exibiu associacao com o polimorfismo rs1873147. A associacao significante com rs742071 foi detectada apenas com a combinacao de amostras. Em sintese, os resultados demonstram a associacao dos polimorfismos localizados na regiao 1p36 (rs742071), 15q22.2 (rs1873147) e 17q22 (rs227731), com a suscetibilidade genetica ao desenvolvimento de FL/PNS na populacao brasileira, sendo observada uma influencia da diversidade populacional nessas associacoes, uma discreta associacao dos polimorfismos rs7590268 (2p21) e rs8001641 (13q31.1) com FL/PNS e uma modesta associacao de um haplotipo no gene VAX1, sugerindo um efeito com baixa penetrância em FL/PNS. Abstract