Acromelic frontonasal "dysplasia": further delineation of a subtype with brain malformation and polydactyly (Toriello syndrome).

We report on a stillborn boy with frontonasal malformation (Sedano-Jiràsek type D-DeMyer type I), associated with encephalocoele, occipital meningocele and preaxial polydactyly of the feet. This form of frontonasal dysplasia was documented previously in a few other cases with various combinations of postaxial polydactyly, tibial hypoplasia, epibulbar dermoid, occipital encephalocoele, corpus callosum agenesis and Dandy-Walker malformation. Most cases are sporadic.     

Acromelic frontonasal “dysplasia”: Further delineation of a subtype with brain malformation and polydactyly (Toriello syndrome)

We report on a stillborn boy with frontonasal malformation (Sedano-J?iràsek type D—DeMyer type I), associated with encephalocoele, occipital meningocele and preaxial polydactyly of the feet. This form of frontonasal dysplasia was documented previously in a few other cases with various combinations of postaxial polydactyly, tibial hypoplasia, epibulbar dermoid, occipital encephalocoele, corpus callosum agenesis and Dandy-Walker malformation. Most cases are sporadic.     

Triphalangeal thumb and brachy-ectrodactyly syndrome

Two patients with triphalangeal thumbs-ectrodactyly syndrome are described. The first case is a 4-year-old female with triphalangeal thumbs, preaxial polydactyly with rudimentary polydactyly of the 3rd finger of the right hand and ectro-syndactyly of feet. Her stillborn sister had triphalangeal thumbs and ectrodactyly of feet. The mother has triphalangeal thumbs, brachy-syndactyly of the left foot and ectro-syndactyly of the right one. The maternal grandmother has syndactyly of 1st, 2nd, 3rd toes and hypoplasia of the 3rd toe on the right foot. The second case is sporadic and shows triphalangeal thumbs, preaxial polydactyly of the right hand and bilateral lobster-claw feet. Our observations confirm the variability of clinical expression and support the autosomal dominant inheritance of the syndrome.     

Array-CGH in a series of 30 patients with mental retardation, dysmorphic features, and congenital malformations detected an interstitial 1p22.2-p31.1 deletion in a patient with features overlapping the Goldenhar syndrome

Genosensor Array 300 (Abbott) is a multiplex platform for array-based comparative genomic hybridization that detects unbalanced genomic aberrations including whole chromosome gains/losses, microdeletions, duplications and unbalanced subtelomeric rearrangements. A series of 30 patients with unexplained mental retardation, dysmorphic features, congenital abnormalities and normal high resolution karyotype and FISH subtelomeric studies were analyzed using Genosensor Array 300 array-CGH. We identified a chromosomal aberration in one patient with an interstitial 1p31.1 deletion. FISH analysis with BACs specific probes of the 1p region confirmed the interstitial 1p22.2-p31.1 deletion. The patient was a 20-year-old man with short stature, facial dysmorphism including asymmetry, scoliosis, severe psychomotor delay and an epibulbar dermoid cyst. The phenotype was compatible with Goldenhar syndrome despite the absence of asymmetric ears. This observation is of interest since it could be a clue in the search for the genes responsible for Goldenhar syndrome. This study demonstrates the utility of the array-CGH technology in detecting interstitial deletions.     

Townes-Brocks syndrome

Townes-Brocks syndrome (TBS) is an autosomal dominant disorder with multiple malformations and variable expression. Major findings include external ear anomalies, hearing loss, preaxial polydactyly and triphalangeal thumbs, imperforate anus, and renal malformations. Most patients with Townes-Brocks syndrome have normal intelligence, although mental retardation has been noted in a few.     

Novel donor splice site mutation of ABCG5 gene in sitosterolemia

In a patient with sitosterolemia, we found two different mutations of the ATP-binding cassette, subfamily G, member 5 (ABCG5) gene. The first is a missense mutation that changes the amino acid residue at position 419 from arginine to histidine, i.e., R419H. The second is a novel splicing mutation affecting the invariant guanine at the first base of the donor splice site of intron 12, i.e., IVS12 + 1G --> A. The father of the patient is heterozygous for the missense mutation, and the mother is heterozygous for the splicing mutation. No mutations were found in the sister of the patient. Up until now, the missense mutation has only been found in Japanese patients with sitosterolemia. We believe that R419H in our Chinese patient may have the same origin as the mutation in the Japanese patients with sitosterolemia.     

GLI3‐related polydactyly: a review

GLI3 mutations are known to be associated with nine syndromes/conditions in which polydactyly is a feature. In this review, the embryology, pathogenesis, and animal models of GLI3‐related polydactyly are discussed first. This is followed by a detailed review of the genotype–phenotype correlations. Based on our review of the literature and our clinical experiences, we recommend viewing GLI3‐related syndromes/conditions as four separate entities; each characterized by a specific pattern of polydactyly. These four entities are: the preaxial polydactyly type IV‐Greig‐acrocallosal spectrum, postaxial polydactyly types A/B, Pallister–Hall syndrome (PHS), and oral‐facial‐digital overlap syndrome. We also provide illustrative clinical examples from our practice including a family with a novel GLI3 mutation causing PHS. The review also introduces the term ‘Forme Fruste’ preaxial polydactyly and gives several conclusions/recommendations including the recommendation to revise the current criteria for the clinical diagnosis of PHS.     

Complex postaxial polydactyly types A and B with camptodactyly,hypoplastic third toe,zygodactyly and other digit anomalies caused by a novel GLI3 mutation

Polydactyly is a phenotypically and genetically highly heterogeneous limb malformation with preaxial and postaxial subtypes and subtypes A and B. Most polydactyly entities are associated with GLI3 mutation. We report on 10 affected individuals from a large Pakistani kindred initially evaluated as a possible new condition. The phenotype is postaxial polydactyly types A and B associated with zygodactyly, postaxial webbing of toes and additional features not previously reported for isolated polydactyly such as camptodactyly, hypoplasia of third toe, and wide space between hallux and second toe. Hypothesizing that the disorder could have resulted from a mutation in a novel gene responsible for polydactyly, we launched a genetic investigation. By linkage mapping and exome sequencing in the most severe case, we identified novel heterozygous frameshift mutation NM_000168.5 (GLI3): c.3635delG (p.(Gly1212Alafs*18)) but did not detect any other possibly deleterious mutation that could explain the unusual features of camptodactyly, hypoplasia of third toe and wide space between first and second toes. Our findings further expand the phenotypic variability of GLI3 polydactyly. We also present a review of GLI3-associated isolated limb anomalies, which indicates that GLI3 mutation leads primarily to two well-established polydactyly types: postaxial types A and B and crossed polydactyly type I. In addition, a variety of other minor digit anomalies generally accompany polydactyly, and there is no straightforward genotype-polydactyly phenotype correlation.     

Detection of heterozygous SALL1 deletions by quantitative real time PCR proves the contribution of a SALL1 dosage effect in the pathogenesis of Townes-Brocks syndrome

Townes-Brocks syndrome (TBS) is an autosomal dominantly inherited disorder characterized by ear, anal, limb, and renal malformations, and results from mutations in the gene SALL1. All SALL1 mutations previously found in TBS patients create preterminal termination codons. In accordance with the findings of pericentric inversions or balanced translocations, TBS was initially assumed to be caused by SALL1 haploinsufficiency. This assumption was strongly contradicted by a Sall1 mouse knock-out, because neither hetero- nor homozygous knock-out mutants displayed a TBS-like phenotype. A different mouse mutant mimicking the human SALL1 mutations, however, showed a TBS-like phenotype in the heterozygous situation, suggesting a dominant-negative action of the mutations causing TBS. We applied quantitative real time PCR to detect and map SALL1 deletions in 240 patients with the clinical diagnosis of TBS, who were negative for SALL1 mutations. Deletions were found in three families. In the first family, a 75 kb deletion including all SALL1 exons had been inherited by two siblings from their father. A second, sporadic patient carried a de novo 1.9-2.6 Mb deletion including the whole SALL1 gene, and yet another sporadic case was found to carry an intragenic deletion of 3384 bp. In all affected persons, the TBS phenotype is rather mild as compared to the phenotype resulting from point mutations. These results confirm that SALL1 haploinsufficiency is sufficient to cause a mild TBS phenotype but suggest that it is not sufficient to cause the severe, classical form. It therefore seems that there is a different contribution of SALL1 gene function to mouse and human embryonic development.     

Co-occurrence of three different mutations in the bilirubin UDP-glucuronosyltransferase gene in a Chinese family with Crigler-Najjar syndrome type I and Gilbert's syndrome

Crigler-Najjar syndrome type I is a severe form of hereditary unconjugated hyperbilirubinemia and is caused by homozygous or compound heterozygous mutations of the bilirubin UDP-glucuronosyltransferase gene (UGT1A1). We analyzed the bilirubin UDP-glucuronosyltransferase gene in a female Chinese patient with Crigler-Najjar syndrome type I. Relatives of the patient were also analyzed. The patient was homozygous for a nonsense mutation of R341X. The patient's father, sister and brother, all diagnosed with Gilbert's syndrome, were compound heterozygotes of R341X, P229Q, and an insertion mutation of the TATA box [A(TA)7TAA]. Heterozygotes of nonsense mutations (Q331X and C280X) in our previous study had either Crigler-Najjar syndrome type II or Gilbert's syndrome, but heterozygotes of R341X (mother and grandmothers) were normal. An in vitro expression study of homozygous and heterozygous models of R341X showed 0 and 58%, respectively, of normal enzyme activity. Therefore, the present results indicate that carriers of the nonsense mutation could be normal for plasma bilirubin concentration, Gilbert's syndrome and Crigler-Najjar syndrome type II. The results also suggest the importance of the accumulation of prevalent or polymorphic mutation in the etiology of Gilbert's syndrome and Crigler-Najjar syndrome type II.     

The Greig cephalopolysyndactyly syndrome: report of a family and review of the literature

The Greig cephalopolysyndactyly syndrome in characterized by a set of craniofacial defects (macrocephaly, broad nasal root) leading to peculiar facial appearance, postaxial (occasionally preaxial) polydactyly of hands, preaxial (rarely postaxial) polydactyly of feet, and syndactyly of fingers and toes. Occasionally other skeletal or nonskeletal defects are present. This is an autosomal dominant trait with complete penetrance and variable expressivity. Prognosis for mental and physical development of the affected patients is good, surgery being indicated primarily for aesthetic and functional correction of polydactyly and syndactyly. We report on a Brazilian family in whom the mother and two of three sons were affected.     

Goldenhar综合征一例报道及文献复习

目的探讨Goldenhar综合征的发病机制、临床表现、诊断及治疗,以提高,临床医生对本病的认识。方法报道一例Goldenhar综合征患儿的临床资料,并复习通过文献数据库检索的相关文献。结果Goldenhar综合征病因尚不清楚,临床表现具有高度多样性,包括眼部畸形、耳部畸形、颜面畸形、脊柱异常、心脏及其它脏器等的发育缺陷;诊断主要依靠特征性的临床表现及头颅、脊柱的影像学检查;治疗以整形外科手术为主,如无合并严重脏器畸形,一般预后良好;产前胎儿超声对产前诊断有一定帮助。结论Goldenhar综合征是一种涉及全身多个器官系统的先天性畸形,详细的体格检查,并进行影像学检查,避免因诊断不全而延误对患者进行及时的诊治非常重要。     

A Novel ZRS Mutation Leads to Preaxial Polydactyly Type 2 in a Heterozygous Form and Werner Mesomelic Syndrome in a Homozygous Form

Point mutations in the zone of polarizing activity regulatory sequence (ZRS) are known to cause human limb malformations. Although most mutations cause preaxial polydactyly (PPD), triphalangeal thumb (TPT) or both, a mutation in position 404 of the ZRS causes more severe Werner mesomelic syndrome (WMS) for which malformations include the distal arm or leg bones in addition to the hands and/or feet. Of more than 15 reported families with ZRS mutations, only one homozygous individual has been reported, with no change in phenotype compared with heterozygotes. Here, we describe a novel point mutation in the ZRS, 402C>T (AC007097.4:g.105548C>T), that is transmitted through two Mexican families with one homozygous individual. The homozygous phenotype for this mutation, WMS, is more severe than the numerous heterozygous individuals genotyped from both families who have TPT and PPD. A mouse transgenic enhancer assay shows that this mutation causes an expansion of the enhancer's expression domain in the developing mouse limb, confirming its pathogenicity. Combined, our results identify a novel ZRS mutation in the Mexican population, 402C>T, and suggest that a dosage effect exists for this ZRS mutation.     

Two novel heterozygous mutations of EVC2 cause a mild phenotype of Ellis-van Creveld syndrome in a Chinese family

Ellis–van Creveld syndrome (EvC, chondroectodermal dysplasia; OMIM 225500) is an autosomal recessive skeletal dysplasia with associated multisystem involvement. The syndrome is characterized by short limbs, short ribs, postaxial polydactyly, dysplastic nails, and abnormal teeth. Congenital heart defects occur in 50–60% of cases. In this study, we report EvC in a 6‐year‐old Chinese girl with hypodontia and polydactyly, mild short stature, and abnormalities of the knee joints. No signs of short ribs, narrow thorax, or congenital heart defects were found in this patient. The EvC phenotype shares some similarity with Weyers acrofacial dysostosis (Weyer; OMIM 193530), an autosomal dominant disorder clinically characterized by mild short stature, postaxial polydactyly, nail dystrophy, and dysplastic teeth. Mutations in EVC or EVC2 are associated with both EvC syndrome and Weyers acrodental dysostosis, but the two conditions differ in the severity of the phenotype and their pattern of inheritance. In this study, two novel heterozygous EVC2 mutations, IVS5‐2A > G and c.2653C > T (Arg885X), were identified in the patient. The IVS5‐2A > G mutation was inherited from the patient's mother and the c.2653C > T from her father. Her parents have no phenotypic symptoms similar to those of the patient. These findings extend the mutation spectrum of this malformation syndrome and provide the possibility of prenatal diagnosis for future offspring in this family. © 2011 Wiley‐Liss, Inc.     

Lesch-Nyhan disease in a female with a clinically normal monozygotic twin

Lesch-Nyhan disease (LND) is an inborn error of purine metabolism caused by defective activity of the enzyme hypoxanthine guanine phosphoribosyl transferase (HPRT, EC 2.4.2.8), resulting from mutation in the corresponding gene on the long arm of the X chromosome (Xq26). The classic phenotype occurs almost exclusively in males and is characterized by hyperuricemia, mental retardation, severe dystonia, and self-injurious behavior. Heterozygous carrier females are usually clinically normal. However, a small number of clinically affected females have been described. In all previous cases there was a mutation in one HPRT allele and non-random inactivation of the X chromosome carrying the normal HPRT gene. We have analyzed a female MZ twin pair discordant for Lesch-Nyhan disease. The mother and both twins are heterozygous carriers of a HPRT splicing mutation (IVS8 + 4A > G; c.609 + 4A > G) and all three express the mutant allele at similar frequencies in peripheral blood T cells. The mother and one sister are clinically normal. In the affected twin, the clinical phenotype is classical for Lesch-Nyhan disease, despite the fact that HPRT activity in the blood was also normal. X inactivation analysis showed a skewed pattern in the fibroblasts of the affected twin sister, with the X chromosome carrying the normal HPRT allele preferentially inactivated. As in many other reported cases of X-linked diseases, the discordant phenotype of the two monozygous twin sisters suggests that the process responsible for monozygotic twinning can trigger skewed X inactivation.     

Crossed polydactyly type I in a mother and son: an autosomal dominant trait?

In a Japanese family, a propositus and his mother had crossed polydactyly type I. A maternal grandaunt also had preaxial polydactyly of the feet. The findings that both of the mother and son had the identical type of polydactyly are consistent with an autosomal dominant inheritance with variable expressivity. Other explanations include X-linked recessive inheritance, polygenic inheritance, and a chance occurrence of the 2 different kinds of polydactyly.     

Fragile X mutation and FG syndrome-like phenotype

We present data on 4 mentally retarded brothers, 2 of whom were dizygotic twins with congenital hypotonia, constipation, head size disproportionately large for length or height, and a combination of minor anomalies suggestive of FG syndrome. These brothers have a mentally retarded full sister with similar minor anomalies and an older half-brother with the Martin-Bell syndrome. The mother is mentally retarded; 4 of 7 individuals are positive for fragile X, but all have a CGG expansion ranging from 0.2–2 to 4 kb. Although the phenotype is not completely typical of the FG syndrome and the coincidence of the FMR1 mutation and segregation of the MCA/MR phenotype are highly unlikely, the FMR1 mutation may affect morphogenesis more extensively and differently than the Martin-Bell syndrome does to effect an FG syndromelike phenotype in certain families. This phenotype does not appear to be a contiguous gene syndrome, but an effect of the FMR1 mutation on an adjacent gene must be considered. © 1996 Wiley-Liss, Inc.