Conjoined twins discordant for cleft lip and palate

Female thoraco-omphalopagus twins were of equal size and had similar abnormalities related to the twinning site. However, one twin was more severely affected and also had cleft lip and palate which the co-twin did not have. The implications of this are discussed.     

Phenotypic discordance in a family with monozygotic twins and nonsyndromic cleft lip and palate: Follow‐up

Axenfeld‐Rieger anomaly (ARA) is an autosomal dominant disorder of the anterior chamber of the eye that includes a prominent and anteriorly displaced Schwalbe line and an iridocorneal synechiae, and is associated with iris hypoplasia, corectopia, and hole formation. Extraocular developmental abnormalities, especially of the teeth, facial bones, and periumbilical skin, have also been reported with ARA, in the context of the so‐called Axenfeld‐Rieger syndrome (ARS). Genetic heterogeneity exists, as ARA maps to chromosome 6p25, whereas ARS can be linked to both chromosome 4q25 and chromosome 13q14. Here we describe a new family in which ARA is associated with cardiac malformations and sensorineural hearing loss. No abnormalities of the teeth, facial bone, or periumbilical skin, which are considered of paramount importance in the diagnosis of ARS, were observed in our patients. Genetic studies will clarify if these patients represent a unique phenotypic expression of ARS or constitute the clinical presentation of a new genetic syndrome. © 2002 Wiley‐Liss, Inc.     

Revisiting the recurrence risk of nonsyndromic cleft lip with or without cleft palate

Sub-epithelial defects (i.e., discontinuities) of the superior orbicularis oris (OO) muscle appear to be a part of the phenotypic spectrum of cleft lip with or without cleft palate (CL?±?P). Analysis of the OO phenotype as a clinical tool is hypothesized to improve familial recurrence risk estimates of CL?±?P. Study subjects (n?=?3,912) were drawn from 835 families. Occurrences of CL?±?P were compared in families with and without members with an OO defect. Empiric recurrence risks were calculated for CL?±?P and OO defects among first-degree relatives (FDRs). Risks were compared to published data and/or to other outcomes of this study using chi-square or Fisher's exact tests. In our cohort, the occurrence of CL?±?P was significantly increased in families with OO defects versus those without (P?相似文献   

非综合征性唇腭裂患者四例microRNA的表达分析

目的寻找可能导致非综合征性唇腭裂的microRNA。方法采用丹麦Exiqon公司microRNA基因芯片技术对4例非综合征性唇腭裂患者的唇腭组织与4例正常胎儿的脐带组织进行检测比对。结果实验组（唇腭裂患儿组）与对照组（正常胎儿组）出现差异表达的microRNA共254条,其中实验组较对照组表达上调的181条,表达下调的73条。结论差异表达较显著的microRNA可能与非综合征性唇腭裂的发生存在关联。     

Two pairs of male monozygotic twins discordant for Wiedemann-Beckwith syndrome

Wiedemann-Beckwith syndrome (WBS) is a congenital anomaly syndrome which classically consists of exomphalos, macroglossia, and gigantism. The syndrome is also associated with a variety of minor anomalies and affected individuals have an increased risk of developing rare embryonal cell tumors. To date, 15 monozygotic (MZ) twin pairs have been reported of which 13 are discordant for WBS. All except one pair of the discordant WBS twin pairs have been female. We report two pairs of male MZ twins, each discordant for WBS. © 1996 Wiley-Liss, Inc.     

Analysis of the recurrence patterns for nonsyndromic cleft lip with or without cleft palate in the families of 3,073 Danish probands

The identification of several putative susceptibility loci for nonsyndromic cleft lip with or without cleft palate (CL ± P) has sparked a renewed interest in the genetics of this condition. However, prior to undertaking linkage studies for complex traits such as CL ± P it is desirable to have some understanding of the number and nature of the loci involved in disease susceptibility. The ability to obtain valid estimates of these parameters is contingent on the availability of family data which are unbiased by factors that distort the true familial recurrence pattern. In an effort to obtain such data, 2 centralized data repositories (the Danish Central Person Registry and the Danish Facial Cleft Database), were linked and used to estimate the risks to first, second, and third-degree relatives of 3,073 CL ± P probands born in Denmark from 1952 to 1987. Analyses of these data excluded single locus and additive multilocus inheritance of CL ± P, and provided evidence that CL ± P is most likely determined by the effects of multiple interacting loci. Under a multiplicative model, no single locus can account for more than a threefold increase in the risk to first-degree relatives of CL ± P probands. These data provide further evidence that nonparametric linkage methods (ex. affected relative pair studies) are likely to represent a more realistic approach for identifying CL ± P susceptibility loci, than are traditional pedigree-based methods. However, at least 100 and more realistically several hundred (300–500) affected sib pairs are likely to be required to detect linkage to CL ± P susceptibility loci. © 1996 Wiley-Liss, Inc.     

Association between IRF6 and nonsyndromic cleft lip with or without cleft palate in four populations.

PURPOSE: The interferon regulatory factor 6 (IRF6), the gene that causes van der Woude syndrome has been shown to be associated with nonsyndromic cleft lip with or without palate in several populations. This study aimed to confirm the contribution of IRF6 to cleft lip with or without palate risk in additional Asian populations. METHODS: A set of 13 single nucleotide polymorphisms was tested for association with cleft lip with or without palate in 77 European American, 146 Taiwanese, 34 Singaporean, and 40 Korean case-parent trios using both the transmission disequilibrium test and conditional logistic regression models. RESULTS: Evidence of linkage and association was observed among all four populations; and two specific haplotypes [GC composed of rs2235373-rs2235371 (p.V274I) and AAG of rs599021-rs2235373-rs595918] showed the most significant over- and undertransmission among Taiwanese cases (P=9x10(-6) and P=5x10(-6), respectively). The AGC/CGC diplotype composed of rs599021-rs2235373-rs2013162 showed almost a 7-fold increase in risk among the Taiwanese sample (P<10(-3)). These results confirmed the contribution of this gene to susceptibility of oral clefts across different populations; however, the specific single nucleotide polymorphisms showing statistical significance differed among ethnic groups. CONCLUSION: The high-risk genotypes and diplotypes identified here may provide a better understanding of the etiological role of this gene in oral clefts and potential options for genetic counseling.     

Clozapine-induced weight gain: a study in monozygotic twins and same-sex sib pairs

To assess the relative contribution of genetic factors in antipsychotic-induced weight gain, we explored the similarity in body mass index (BMI) (kg/m(2)) change under clozapine only (clozapine DeltaBMI) and upon additional inclusion of BMI change under prior antipsychotic medication (total DeltaBMI) of five monozygotic twins in comparison with seven same-sex sibs. Twin and sib pairs were identified by a telephone screening of 786 office-based psychiatrists. Measured data on weight and other clinical variables were obtained cross-sectionally and retrospectively from medical records. We found greater similarity in total DeltaBMI in monozygotic twins (intrapair difference 2.78+/-3.41 kg/m(2)) than in same-sex sibs (5.55+/-4.35 kg/m(2)), resulting in heritability estimates of h(2)=0.8 and A=0.45 (ACE twin model). However, intrapair differences in clozapine DeltaBMI were similar between twins (4.18+/-4.27 kg/m(2)) and sibs (4.68+/-4.88 kg/m(2)). We hypothesize that the weight plateau achieved under clozapine is influenced by genetic factors. The weight gain achieved during pretreatment with other antipsychotics seems to limit clozapine-induced weight gain, thus presumably explaining why heritability/similarity in monozygotic twins in comparison with same-sex sibs is greater for total DeltaBMI than for clozapine DeltaBMI. An important caveat is that, owing to the sample size, the heritability estimates have a large standard error and thus have to be interpreted with caution.     

Variation in IRF6 contributes to nonsyndromic cleft lip and palate

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common craniofacial birth defect which results in lifelong medical and social consequences. While there have been a number of attempts to identify the genes responsible for this disorder, the results have not been consistent among populations and no single gene has been identified as playing a major susceptibility role. Van der Woude syndrome, a disorder characterized by lower-lip pits with or without cleft lip/palate, results in many cases from mutations in the interferon regulatory factor 6 (IRF6) gene. Recently, Zucchero et al. [2004: N Engl J Med 351:769-780] detected an association between SNPs in IRF6 and NSCLP in a number of different populations. A subsequent study by Scapoli et al. [2005: Am J Hum Genet 76:180-183] confirmed this association in an Italian population. We examined the same SNPs as Scapoli et al. [2005] in our large, well-characterized sample of NSCLP families and trios, and also detected an altered transmission of IRF6 alleles. This additional confirmation further strengthens the IRF6 association and suggests that IRF6 plays a role in NSCLP susceptibility.     

Evidence of the involvement of the DHFR gene in nonsyndromic cleft lip with or without cleft palate

Studies aimed at evidencing genetic causes for neural tube defect (NTD) occurrence have often provided the inspiration for orofacial cleft aetiology investigations. The correlation between the two congenital malformations is provided by the similar incidence timing and the involvement of structures localized in the midline of the embryo. This connection is corroborated by the existence of a number of genes involved in both malformations. In this article, we considered the dihydrofolate reductase (DHFR) gene, previously seen implicated in NTDs, as a candidate for cleft lip with or without cleft palate (CL/P) risk. Four SNPs mapping on the DHFR gene were genotyped for 400 Italian CL/P triads, using TaqMan^® approach. The rs1677693 provided evidence of association, even if at borderline level (P value 0.049). In particular, the variant allele seems to have a protective effect OR = 0.80 (95% C.I. 0.64–0.99). Moreover, the combination of rs1677693(A)-rs1650723(G) alleles showed a significant association OR 0.64 (95% C.I. 0.47–0.86) (P value = 0.006). This represents the first attempt to demonstrate a role for DHFR in CL/P aetiology, howbeit the study of such gene deserves a deepening.     

Evidence for linkage of nonsyndromic cleft lip with or without cleft palate to a region on chromosome 2

Results from a genome-wide screen of 10 multiplex families ascertained through probands with nonsyndromic cleft lip with or without cleft palate (CL/P) in Mexico, Argentina, and the United States yielded suggestive evidence of linkage to chromosomes 2, 6, 17 and 18. Fine mapping excluded all regions except chromosome 2. Subsequent analysis was performed on the original 10 families plus an additional 16 families using 31 markers on chromosome 2. This analysis showed intriguing evidence of linkage to 2q (Zlr=2.26, empirical P-value=0.028 in a chromosome-wide analysis). Transmission disequilibrium tests also revealed evidence of linkage and disequilibrium for two markers in this region (D2S168 and D2S1400 with P-values=0.022 and 0.006, respectively). A subset of these 26 families provided additional evidence for a susceptibility gene for CL/P on 2q, suggesting that further studies of genes in this region are warranted.     

Study of folate receptor genes in nonsyndromic familial and sporadic cleft lip with or without cleft palate cases

Folate receptor family members (FOLRs) mediate the delivery of 5-methyltetrahydrofolate to the interior of, out of within, or between cells in a process known as potocytosis. Three FOLRs and a pseudogene map to 11q13.4. The aim of this study was to verify whether FOLRs could be responsible for the onset of nonsyndromic cleft lip with or without cleft palate (CL/P). Linkage and linkage disequilibrium between genetic markers and disorder were analyzed. Patients and their mothers from 71 familial CL/P pedigrees and 75 sporadic cases from Italian population were investigated by PCR-SSCP analysis. Data from mutation scanning allowed us to find only a silent mutation in FOLR1 present in a mother and her child. Our findings do not support FOLR1 and FOLR2 genes in the onset of CL/P.     

Expression and association data strongly support JARID2 involvement in nonsyndromic cleft lip with or without cleft palate

Nonsyndromic cleft lip with or without cleft palate (CL/P) affects approximately 1 in 1,000 births. Genetic studies have provided evidence for the role of several genes and candidate loci in clefting; however, conflicting results have frequently been obtained and much have to be done to unravel the complex genetics of CL/P. In the present investigation we have focused on the candidate region in 6p23, a region that have been found linked to CL/P in several investigations, in the attempt to find out the susceptibility gene provisionally named OFC1. Gene expression experiments in mice embryo of positional candidate genes revealed that JARID2 was highly and specifically expressed in epithelial cells in merging palatal shelves. A family‐based linkage disequilibrium study confirmed the pivotal role of JARID2 in orofacial development and strongly supports a role for this gene in CL/P etiology (multiallelic haplotype test P=6×10^?5). Understanding the molecular role of JARID2 within facial development may offer additional information to further unravel the complex genetics of CL/P. Hum Mutat 31:1–7, 2010. © 2010 Wiley‐Liss, Inc.     

IRF6基因rs2235371位点多态性与非综合征性唇裂伴或不伴腭裂的相关性研究

目的 探讨干扰素调节因子6 (interferon regulatory factor 6,IRF6)基因rs2235371位点820G＞A单核苷酸多态性与非综合征性唇裂伴或不伴腭裂(nonsyndromic cleft lip with or without cleft palate,NSCL士P)的相关性.方法 收集106例患者及其父母以及129名对照及其父母的核心家庭标本,用聚合酶链反应-限制性片段长度多态性的方法进行IRF6基因rs2235371位点单核苷酸多态性检测;用人群关联研究、传递不平衡检验(transmission disequilibrium test,TDT)、单倍型相对风险率(haplotype-based haplotype relative risk,HHRR)、家系为基础的关联检验(family-based association tests,FBAT)等方法进行统计分析.结果 病例组与对照组相比,子代的基因型分布差异无统计学意义(P＞0.05),而等位基因频率比较差异有统计学意义(P＜0.05);母亲组基因型分布差异有统计学意义(P＜0.05);按唇腭裂类型分类后,单纯唇裂组子代基因型分布和等位基因的频率与对照组相比差异均有统计学意义(P＜0.05);而唇腭裂组基因型分布和等位基因频率差异均无统计学意义(P＞0.05).传递不平衡检验提示,rs2235371位点的G等位基因在NSCL±P核心家庭中存在传递不平衡(x2=5.56,P=0.024).HHRR检验x2=5.115,P=0.024,OR=1.674,95％CI:1.069～2.621;FBAT检验Z=2.218,P=0.027.结论 在中国北方人群中IRF6基因rs2235371位点突变与非综合征性唇腭裂存在关联.