对称性双手多指、双足多趾畸形1例

先天性多指(趾)畸形又称重复指(趾),是在新生儿中常见的疾病.病因尚不明确,多指(趾)畸形在手与足的先天性畸形中较常见,有时可与并指、短指或其他先天性畸形同时存在,足部畸形趾以单个较多见,多生长在拇趾或小趾胖,而第2、3、4足趾处少见[1].有关对称性多指(趾)畸形并伴有家族遗传性的报道较少见.现将我科于2009年9月收治的1例有遗传倾向的先天性对称性多指及多趾畸形并伴有独立跖骨的病例报道如下.     

遗传性多指（趾）畸形及相关基因研究进展

先天性肢异常是人群中较为常见的遗传缺陷，而多指畸形是最常见的先天手畸形。本综述了多指畸形的分类及遗传特点，总结了脊椎动物中肢发育相关基因的研究现状，以及人类多指畸形相关基因的研究进展，并对其研究意义及前景作了展望。     

遗传性多指(趾)畸形及相关基因研究进展

先天性肢异常是人群中较为常见的遗传缺陷，而多指（趾）畸形是最常见的先天手（足）畸形。本文综述了多指（趾）畸形的分类及遗传特点；总结了脊椎动物中肢发育相关基因的研究现状，以及人类多指（趾）畸形相关基因的研究进展；并对其研究意义及前景作了展望     

先天性多指畸形一家系6例

先天性多指畸形是人群中较为常见的出生缺陷之一,具有较高的遗传异质性,临床表型复杂,既可以独立发生,又可作为某种综合征的部分症状出现。本文通过家系调查报道了一先天性多指畸形家系,介绍了家系中6例患者的主要临床特征,并对相关文献进行复习。     

非综合征型多指(趾)致病基因的研究进展

多指是最常见的先天性肢体异常 ,遗传方式多为常染色体显性遗传。迄今为止 ,用连锁分析的方法对多个非综合征型多指 (趾 )畸形家系进行了基因定位和致病基因的突变分析。本文就近年来在多指 (趾 )畸形致病基因研究方面做一综述。     

非综合征型多指（趾）致病基因的研究进展

多指是最常见的先天性肢体异常，遗传方式多为常染色体显性遗传。迄今为止，用连锁分析的方法对多个非综合征型多指(趾)畸形家系进行了基因定位和致病基因的突变分析。本文就近年来在多指(趾)畸形致病基因研究方面做一综述。     

多指 (趾) 致病基因研究进展

多指 (趾) 畸形是最常见肢体畸形之一, 具有遗传性, 分为综合征型和非综合征型两大类型。 非综合征型按照解剖位置可分为轴前、 轴后及中央型多指, 综合征型多指 (趾) 是指除多指表型以外, 还 伴随其他症状。 近些年, 多用连锁分析、 全外显子测序等对相关致病基因的定位及突变进行分析, 并通过 分析突变的基因所表达的蛋白, 了解其对相关信号通路可能产生的影响。 通过总结多指 (趾) 畸形主要致 病基因最新研究及影响肢体前后模式主要通路, 旨在了解多指 (趾) 致病基因的研究方向和热点, 为今后 能在胚胎阶段阻断多指 (趾) 形成的研究提供依据和思路。     

轴前多指致病基因研究进展

轴前多指（PPD）是人类常见的肢体畸形。Shh在胚胎肢芽前部的异位表达可直接导致PPD的发生，而Lmbr1基因结构的变异与多指表型密切相关。PPD的候选基因定位于人染色体7q36上的450kb内。最近对多个家系的研究发现，Lmbr1作为顺式调控元件对Shh的远距离调控是引起PPD的关键分子机制。     

多指并指畸形胎儿的无创产前筛查报告分析

目的研究并探讨超声连续顺序追踪法在筛查多指并指畸形胎儿中的效果以及最佳孕周。方法选取2013年12月~2017年1月期间于我院进行产前检查的7896例孕妇作为研究对象,所有孕妇均通过超声连续顺序追踪法进行诊断,将筛查结果与胎儿出生或引产后的实际多指并指畸形情况进行比较,分析超声连续顺序追踪法在筛查胎儿多指和并指畸形中的效果以及最佳筛查孕周。结果利用彩色多普勒超声对7896例孕妇进行筛查后共诊断出5例多指并指患儿,其中多指畸形3例,并指畸形2例。漏诊9例,包括多指畸形6例,并指畸形3例,诊断符合率35.71%。孕妇在孕19~24周时期内胎儿手部显示最清晰,共诊断出多指或并指畸形胎儿4例(80%)。结论超声连续顺序追踪法可作为筛查多指并指畸形胎儿的一种手段,但筛查准确率仍有待提高。孕妇在孕19~24周期间是筛查胎儿手部畸形的最佳时机。     

先天性白内障的分子遗传学研究进展

先天性白内障(congenital cataract)是指在孕期或胎儿期由于各种因素使晶状体发育受到影响,是儿童致盲的首要原因之一.先天性白内障有明显的临床异质性和遗传异质性,一般与晶体蛋白基因、缝隙连接蛋白基因、转录因子基因及其他基因突变有关,常见的遗传方式有常染色体显性遗传、常染色体隐性遗传和性染色体连锁遗传,其中以常染色体显性遗传最为常见.近几年先天性白内障的分子遗传学水平有了新的突破,此文就其研究进展进行综述.     

Phenotypic analysis of triphalangeal thumb and associated hand malformations.

Triphalangeal thumb (TPT), a long, finger-like thumb with three phalanges instead of two, is regarded as a subtype of preaxial polydactyly. It can occur as a sporadic disorder, but is more often seen as a dominant familial trait. We describe four white Dutch families in which triphalangeal thumb has variable expression and is sometimes associated with preaxial extra rays, rudimentary postaxial polydactyly, cutaneous syndactyly of the hands, and, rarely, postaxial polydactyly and syndactyly of the feet. A comparison with similar familial conditions reported during the past 10 years is provided. The potential significance of linkage and molecular genetic analysis for better insight into the pathogenesis of complex hand malformations is discussed.     

Molecular analysis of non-syndromic preaxial polydactyly: preaxial polydactyly type-IV and preaxial polydactyly type-I

Human GLI3 gene mutations have been identified in several phenotypes of digital abnormality such as Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, preaxial polydactyly type-IV (PPD-IV) and postaxial polydactyly. However, the different phenotypes resulting from GLI3 mutations have not yet been properly defined. We have experienced two types of digital abnormality without other complicating developmental defects; a family with foot PPD-IV with syndactyly of the third and fourth fingers, and four sporadic cases with biphalangeal thumb polydactyly (PPD-I). The genes responsible for syndactyly of the third and fourth fingers (syndactyly type-I) and PPD-I have not yet been identified; we therefore examined the involvement of the GLI3 gene in these subtypes of digital abnormality. We found a non-sense mutation in the GLI3 gene in the family with foot PPD-IV accompanied with hand syndactyly of the third and fourth fingers, but no mutations were detected in the GLI3 gene in the four other cases with PPD-I alone. Thus, the phenotype of foot PPD-IV accompanied with hand syndactyly of the third and fourth fingers may result from a GLI3 mutation, whereas the PPD-I phenotype alone is not caused by GLI3 gene defect. These results will help to define the phenotypic spectrum of GLI3 morphopathies, which have been recently proposed.     

Clinical and descriptive genetic study of polydactyly: a Pakistani experience of 313 cases

Polydactyly, a common hereditary condition with additional digits in hands and/or feet, is a very attractive model to appreciate clinical and genetic heterogeneity. In order to get an insight into its phenotypic manifestations, we ascertained a cohort of 313 independent families with polydactyly from Pakistan; 35% cases turned out to be familial while 65% were sporadic. In majority of the index cases, polydactyly was presented as an isolated digit defect. Preaxial polydactyly types were 48.24% and postaxial were 51.8%. Familial polydactylies mainly had bilateral and symmetrical presentations, whereas sporadic cases were mostly unilateral and less often symmetrical. In the 313 index subjects a total of 508 limbs with additional digits were recorded. Variable expression was evident as the involvement of upper limbs was more common than the lower, right hand than the left, and left foot than the right. The present cohort establishes interesting epidemiological attributes of polydactyly in the Pakistani population and highlights its extraordinary clinical heterogeneity. Molecular analyses of this cohort are anticipated to elucidate novel genetic factors involved in the origin of additional digits in the growing limb and may provide clues to the role of stochastic factors in the etiology of phenotypic variability in polydactyly.     

A novel ZRS mutation in a Balochi tribal family with triphalangeal thumb, pre-axial polydactyly, post-axial polydactyly, and syndactyly

Limb malformations are one of the most common types of human congenital malformations. Mutations in the ZRS enhancer of Sonic Hedgehog are thought to be responsible for pre-axial polydactyly in multiple independent families. Here, we describe a large Balochi tribal family from Southern Punjab, Pakistan, with a variable set of limb malformations and a novel ZRS mutation. The family has a limb phenotype characterized by triphalangeal thumb, pre-axial polydactyly, and post-axial polydactyly. There is also a high degree of phenotypic heterogeneity with less common clinical findings in the affected family members that include osseous syndactyly of forth-fifth fingers, clinodactyly, hypoplasia of mesoaxial fingers, and bifid halluces. The presentation in most of the affected patients was bilateral and symmetrical. A heterozygous C>A mutation at position 287 of the ZRS enhancer (chr7:156,584,283; hg19) was detected in all affected subjects and is absent from four unaffected family members, 42 unrelated samples, and multiple databases of human variation. Combined, these results identify a novel ZRS287 C>A mutation which leads to a variable spectrum of limb phenotypes.     

Diagnostic problems in a case with mucometrocolpos,polydactyly, congenital heart disease,and skeletal dysplasia

Mucometrocolpos is the distention of the uterus and vagina caused by obstruction to the drainage of genital secretions. Although most cases of mucometrocolpos are sporadic, it may be part of an autosomal recessive condition, known as McKusick-Kaufman syndrome (MKS), including postaxial polydactyly and congenital heart disease as main findings. The diagnosis may be difficult when the presence of additional findings creates an overlap with other syndromes. We report on a female infant with mucometrocolpos, postaxial polydactyly, congenital heart disease, short limbs, short ribs, and chest constriction. The clinicopathological findings are described and discussed in the context of the phenotypic spectrums of MKS and mucometrocolpos concomitant with Ellis van Creveld syndrome. © 1996 Wiley-Liss, Inc.     

Polydactyly: phenotypes,genetics and classification

Polydactyly is one of the most common hereditary limb malformations featuring additional digits in hands and/or feet. It constituted the highest proportion among the congenital limb defects in various epidemiological surveys. Polydactyly, primarily presenting as an additional pre‐axial or post‐axial digit of autopod, is a highly heterogeneous condition and depicts broad inter‐ and intra‐familial clinical variability. There is a plethora of polydactyly classification methods reported in the medical literature which approach the heterogeneity in polydactyly in various ways. In this communication, well‐characterized, non‐syndromic polydactylies in humans are reviewed. The cardinal features, phenotypic variability and molecular advances of each type have been presented. Polydactyly at cellular and developmental levels is mainly a failure in the control of digit number. Interestingly, GLI3 and SHH (ZRS/SHH enhancer), two antagonistic factors known to modulate digit number and identity during development, have also been implicated in polydactyly. Mutations in GLI3 and ZRS/SHH cause overlapping polydactyly phenotypes highlighting shared molecular cascades in the etiology of additional digits, and thus suggesting the lumping of at least six distinct polydactyly entities. However, owing to the extreme phenotypic and clinical heterogeneity witnessed in polydactyly a substantial genetic heterogeneity is expected across different populations and ethnic groups.     

A novel frameshift variant in BHLHA9 underlies mesoaxial synostotic syndactyly associated with postaxial polydactyly

Mesoaxial synostotic syndactyly (MSSD) with phalangeal reduction is an uncommon congenital limb abnormality characterized by central osseous synostosis at a metacarpal level, mesoaxial reduction of the fingers, and preaxial cutaneous syndactyly in toes. In rare cases, the disease is also associated with fifth finger clinodactyly and postaxial polydactyly. It has autosomal recessive inheritance pattern caused by homozygous variants in the gene BHLHA9 mapped at chromosome 17p13.3.In the present study, a consanguineous family of Pakistani origin segregating MSSD in autosomal recessive form was characterized at clinical and genetic levels. Clinically, the diseased individuals have MSSD associated with clinodactyly and polydactyly. Homozygosity mapping followed by Sanger sequencing of BHLHA9 revealed a novel frameshift variant NM_001164405.1: c.409-409delC; p.(His137Thrfs*61) segregating with the disease phenotypes in the family.This is the second report providing evidence of association of polydactyly with MSSD caused by frameshift variant in the gene BHLHA9. The present molecular investigation will support genetic counselling of the local population carrying diseased variants.     

Somatic mutations in NKX2–5, GATA4, and HAND1 are not a common cause of tetralogy of Fallot or hypoplastic left heart

The majority of congenital heart disease (CHD) occurs as a sporadic finding, with a minority of cases associated with a known genetic abnormality. Combinations of genetic and environmental factors are implicated, with the recent and intriguing hypothesis that an apparently high rate of somatic mutations might explain some sporadic CHD. We used samples of right ventricular myocardium from patients undergoing surgical repair of tetralogy of Fallot (TOF) and hypoplastic left heart (HLH) to examine the incidence of somatic mutation in cardiac tissue. TOF is a common form of cyanotic CHD, occurring in 3.3 per 10,000 live births. HLH is a rare defect in which the left side of the heart is severely under-developed. Both are severe malformations whose genetic etiology is largely unknown. We carried out direct sequence analysis of the NKX2–5 and GATA4 genes from fresh frozen cardiac tissues and matched blood samples of nine TOF patients. Analysis of NKX2–5, GATA4, and HAND1 was performed from cardiac tissue of 24 HLH patients and three matched blood samples. No somatic or germline mutations were identified in the TOF or HLH patients. Although limited by sample size, our study suggests that somatic mutations in NKX2–5 and GATA4 are not a common cause of isolated TOF or HLH.     

Congenital scalp defects with distal limb anomalies (Adams-Oliver syndrome): Report of ten cases and review of the literature

We describe one family with 5 affected persons in 4 generations, another family with 2 affected brothers and 3 sporadic cases of the rare syndrome of congenital scalp defects with distal limb deficiency. The manifestations of this syndrome are highly variable. Review of the literature showed 11 families and 19 sporadic cases. In most families the disorder clearly follows an autosomal dominant pattern of inheritance, but in some families with reduced penetrance. Important differential diagnoses are the syndrome of scalp defect and postaxial polydactyly, the syndrome of scalp defect and split-hand defect, amniotic band sequence, and epidermolysis bullosa dystrophica type Bart.     

Congenital pulmonary lymphangiectasis with chylothorax: A heterogeneous lymphatic vessel abnormality

We report on 7 perinatal autopsy cases of primary congenital pulmonary lymphangiectasis (CPL) with bilateral chylothorax. This study demonstrates that primary CPL is often complicated by chylous pleural effusions with ensuing pulmonary hypoplasia. Conversely, CPL appears to be a constant pathological finding in spontaneous congenital chylothorax. These observations indicate a common pathogenesis for both disorders. The basic defects is not an intrinsic lung abnormality, but a developmental error of the lymphatic system resulting in a pulmonary lymphatic obstruction sequence. The cause of CPL is heterogeneous. Apparently, most cases are sporadic occurrences. We report the second instance of CPL in sibs. This indicates that some cases are genetically determined with autosomal recessive inheritance. CPL may also be part of a multiple congenital anomalies (MCA) syndrome such as Noonan, Ullrich-Turner, and Down syndrome. © 1993 Wiley-Liss, Inc.