A preliminary gene map for the Van der Woude syndrome critical region derived from 900 kb of genomic sequence at 1q32-q41

Van der Woude syndrome (VWS) is a common form of syndromic cleft lip and palate and accounts for approximately 2% of all cleft lip and palate cases. Distinguishing characteristics include cleft lip with or without cleft palate, isolated cleft palate, bilateral lip pits, hypodontia, normal intelligence, and an autosomal-dominant mode of transmission with a high degree of penetrance. Previously, the VWS locus was mapped to a 1.6-cM region in 1q32-q41 between D1S491 and D1S205, and a 4.4-Mb contig of YAC clones of this region was constructed. In the current investigation, gene-based and anonymous STSs were developed from the existing physical map and were then used to construct a contig of sequence-ready bacterial clones across the entire VWS critical region. All STSs and BAC clones were shared with the Sanger Centre, which developed a contig of PAC clones over the same region. A subset of 11 clones from both contigs was selected for high-throughput sequence analysis across the approximately 1.1-Mb region; all but two of these clones have been sequenced completely. Over 900 kb of genomic sequence, including the 350-kb VWS critical region, were analyzed and revealed novel polymorphisms, including an 8-kb deletion/insertion, and revealed 4 known genes, 11 novel genes, 9 putative genes, and 3 psuedogenes. The positional candidates LAMB3, G0S2, HIRF6, and HSD11 were excluded as the VWS gene by mutation analysis. A preliminary gene map for the VWS critical region is as follows: [see text] 41-TEL. The data provided here will help lead to the identification of the VWS gene, and this study provides a model for how laboratories that have a regional interest in the human genome can contribute to the sequencing efforts of the entire human genome.     

Microdeletions at chromosome bands 1q32-q41 as a cause of Van der Woude syndrome.

Van der Woude syndrome (VWS) is an autosomal dominant disorder comprising cleft lip and/or cleft palate and lip pits. We reported previously a family whose underlying mutation is a 500-800 kb deletion localized to chromosome bands 1q32-q41 [Sander et al., 1994: Hum Mol Genet 3:576-578]. Along with cleft lip/palate and lip pits, affected relatives exhibit developmental delays, suggesting that the function of a gene nearby may also be disrupted. To further localize the VWS gene we searched for other deletions that cause VWS. An allele loss assay was performed using a novel highly polymorphic marker, D1S3753. From a panel of 37 unrelated individuals, we detected an allele loss in one family, indicating the presence of a deletion. In this family, the phenotype in three generations of affected individuals was confined to the cardinal signs of VWS. Surprisingly, mapping of the new deletion showed that it extended 0.2-1 Mb beyond the proximal breakpoint for the deletion described previously. No deletions were detected in seven cases of popliteal pterygia syndrome, 76 cases of mixed syndromic forms of cleft lip and palate, and 178 cases of nonsyndromic cleft lip and palate. These observations suggest that genetic searches for microdeletions should be routine in screening patients for causes of VWS and may facilitate the positional cloning efforts of the VWS gene and of a nearby gene or genes that may be involved in brain development.     

Popliteal pterygium syndrome: a clinical study of three families and report of linkage to the Van der Woude syndrome locus on 1q32

Popliteal pterygium syndrome (PPS) is a rare autosomal dominant disorder, thought to occur with an incidence of approximately 1 in 300 000 live births. The main clinical manifestations are popliteal webbing, cleft lip, cleft palate, lower lip pits, syndactyly, and genital and nail anomalies. This report describes the clinical features in two families with PPS and one isolated case, showing the range of anomalies found both within and between the families. PPS has some features in common with Van der Woude syndrome (VWS), also inherited as an autosomal dominant condition, with cleft lip/palate and, more distinctively, lower lip pits. Although the gene for VWS has not yet been identified, it has been localised to within 1.6 cM in the region 1q32-41. To determine whether PPS and VWS represent allelic forms of the same gene, three families were genotyped for markers flanking and within the critical region. A multipoint lod score of 2.7 was obtained, with no evidence of recombination, supporting the hypothesis that these two disorders are allelic.     

Analysis of genomewide association signals for nonsyndromic cleft lip/palate in a Kenya African Cohort

Nonsyndromic cleft lip with or without cleft palate is a common birth defect with a wide range of prevalence among different populations, apparently highest in Asians and Amerindians and lowest in Africans. Recent genomewide association studies of European-derived and Asian populations have identified six confirmed loci for this phenotype: 1p22.1, 1q32.2 (IRF6), 8q24, 10q25.3, 17q22, and 20q12. However, there have thus far been no studies of these loci in African patients with nonsyndromic cleft lip with or without cleft palate. We carried out association analysis of SNPs in these six candidate chromosomal regions in 128 nonsyndromic cleft lip with or without cleft palate cases and 105 controls from the Rift Valley of Kenya. We observed no apparent association of this phenotype with any of these SNPs, though there was strong statistical power only for 8q24. These results indicate that at least the 8q24 locus does not play a major role in the pathogenesis of nonsyndromic cleft lip with or without cleft palate in east Africa, supporting locus heterogeneity for susceptibility to this phenotype among different major populations of the world.     

A new case of 2q duplication supports either a locus for orofacial clefting between markers D2S1897 and D2S2023 or a locus for cleft palate only on chromosome 2q13-q21

We report on a pure duplication of the proximal chromosome 2q in a 6.5-year-old boy with V-shaped midline cleft palate and bifid uvula, posteriorly located tongue, and micrognathia (Pierre Robin sequence), celiac disease, failure to thrive, and developmental delay. Cytogenetic and FISH analysis indicated a duplication of chromosome 2q13-q22. In general, pure proximal duplication or triplication of 2q is rare. The clinical features and chromosomal breakpoints of the 10 previously reported patients varied, and no common phenotype or proximal duplication/triplication 2q syndrome could be defined to date. However, based on four previous patients with different orofacial clefts and our case, a locus for orofacial clefting may be located at proximal 2q. The duplication/triplication comprised chromosome 2q13 in all five affected individuals including our patient. Our patient and three previous cases (two with cleft palate only (CPO) and one with cleft lip/palate (CL/P)) showed a cytogenetic breakpoint at 2q13, which could support the presence of a critical dominant gene disrupted by a common breakpoint, however, the fifth case with CPO showed different breakpoints, advocating against the disruption of a critical dominant gene and supporting that the overexpression of a gene(s) on chromosome 2q13-q21 may cause cleft palate only (CPO) and Pierre Robin sequence. Hence, our findings support either the presence of one locus for orofacial clefting (CL/P, CPO, and Pierre Robin sequence) between markers D2S1897 (chromosome 2q12.2) and D2S2023 (chromosome 2q14.2), or alternatively the presence of a locus for CPO and Pierre Robin sequence on chromosome 2q13-q21.     

A novel mutation, 1234del(C), of the IRF6 in a Thai family with Van der Woude syndrome

Van der Woude syndrome (VWS) is an autosomal dominant disorder and the most common cleft syndrome characterized by cleft lip and palate with lip pits. Very recently, mutations in the interferon regulatory factor 6 gene (IRF6) were identified to cause VWS in patients of northern European descent. We describe a Thai family with VWS. The proband, an 8-month-old boy, had bilateral complete cleft lip and palate, and two conical elevations with lip pits on his lower lip. Four other family members had various manifestations of the clefts and lower lip pits. Mutation analysis of the proband and his mother for the entire coding region of IRF6 identified a novel mutation, 1234del(C), in its exon 9. The deletion is expected to result in some amino acid changes followed by truncation at amino acid 435. This observation supports that IRF6 is the gene responsible for VWS across different populations and that haploinsufficiency of the gene disturbs development of the lip and palate.     

Evidence of a locus for orofacial clefting on human chromosome 6p24 and STS content map of the region

Orofacial clefting is genetically complex, no single gene beingresponsible for all forms. It can, however, result from a singlegene defect either as part of a syndrome (e.g. van der Woudesyndrome, Treacher—Colllns syndrome, velo–cardio–facialsyndrome) or as an Isolated phenotypic effect (e.g. X–linkedcleft palate; non–syndromlc, autosomal dominant orofacialclefting). Several studies have suggested that chromosome 6pis a candidate region for a locus involved in orofacial clefting.We have used YAC clones from contigs in 6p25–p23 to investigatethree unrelated cases of cleft lip and palate coincident withchromosome 6p abnormalities. Case 1 has bilateral cleft lipand palate and a balanced translocation reported as 46, XY,t(6, 7)(p23; q36.1). Case 2 has multiple abnormalities Includingcleft lip and palate and was reported as 46, XX, del(6)(p23;pter). Case 3 has bilateral cleft lip and palate and carriesa balanced translocation reported as 46, XX, t(6; 9)(p23;q22.3).We have Identified two YAC clones, both of which cross the breakpointin cases 1 and 3 and are deleted in case 2. These clones mapto 6p24.3 and therefore suggest the presence of a locus fororofacial clefting in this region. The HGP22 and AP2 genes,potentially involved in face formation, have been found to flankthis region, while F13A maps further telomeric in 6p24.3/25.     

Kabuki make-up syndrome is not caused by microdeletion close to the van der Woude syndrome critical region at 1q32-q41.

We reported on a 5-year-old Japanese girl with clinical manifestations of Kabuki make-up syndrome (KMS) and van der Woude syndrome (VWS). Since the concurrence of the two syndromes is known in four patients, including ours, it suggests a common cause. Assuming that the association of the two syndromes was caused by a microdeletion involving the putative KMS/VWS genes, we carried out fluorescence in situ hybridization and microsatellite analyses using PAC clones and dinucleotide repeat markers spanning the VWS1 critical region at 1q32-q41. No deletion was detected at the VWS1 critical region.     

Abnormal brain structure in adults with Van der Woude syndrome

Van der Woude syndrome (VWS) is an autosomal dominant disorder manifested in cleft lip and/or palate and lip pits. Isolated clefts of the lip and/or palate (ICLP) have both genotype and phenotype overlap with VWS. Subjects with ICLP have abnormalities in brain structure and function. Given the similarities between VWS and ICLP, the current study was designed to evaluate the pattern of brain structure of adults with VWS. Fourteen adults with VWS were compared to age- and gender-matched healthy controls. Brain structure was evaluated using magnetic resonance imaging. All subjects with VWS had enlarged volumes of the anterior regions of the cerebrum. Men with VWS had reduced volumes of the posterior cerebrum. Anterior cerebrum volume was negatively correlated with intelligent quotient in the subjects with VWS indicating that the enlargement of this brain region was 'pathologic.' The pattern of brain structure in VWS is nearly identical to those seen in ICLP. In addition, men are affected more severely. Pathologic enlargement of the tissue and a gender effect with men affected more severely are common features of neurodevelopmental disorders supporting the notion that the brain structure of VWS and ICLP may be because of abnormal brain development.     

Developmental expression analysis of the mouse and chick orthologues of IRF6: the gene mutated in Van der Woude syndrome.

Development of the lip and palate involves a complex series of events that are frequently disturbed resulting in the congenital anomalies cleft lip and cleft palate. Van der Woude syndrome (VWS) is an autosomal dominant disorder that is characterised by cleft lip, cleft palate, lower lip pits, and hypodontia. VWS arises as the result of mutations in the gene encoding interferon regulatory factor 6 (IRF6). To provide insights into the role of IRF6 during embryogenesis, we have analysed the expression of this molecule during mouse and chick facial development. Irf6 was expressed in the ectoderm covering the facial processes during their fusion to form the upper lip and primary palate in both mouse and chick. However, while Irf6 was expressed in the medial edge epithelia of the developing secondary palate of the mouse, which fuses as in man, Irf6 was not expressed in the medial edge epithelia of the naturally cleft chick secondary palate. Similarly, Irf6 was found to be down-regulated in the medial edge epithelia of transforming growth factor beta3-null mice, which also exhibit cleft palate. Together, these results support a role for IRF6 during the fusion events that occur during development of the lip and palate.     

Interstitial deletion 4q32-34 with ulnar deficiency: 4q33 may be the critical region in 4q terminal deletion syndrome

We report on an infant with Robin sequence; mild developmental delay; a left ulnar ray defect with absent ulna and associated metacarpals, carpals and phalanges; and a right ulnar nerve hypoplasia. He had a de novo interstitial deletion of 4q32-->q34. The critical region involved in the 4q terminal deletion syndrome may be 4q33. This conclusion was suggested by showing that del(4)(q31qter), del(4)(q32qter), and del(4)(q33qter) result in a similarly severe phenotype. In addition, we propose that genes for distal arm development, in particular for development of the left ulnar ray, central nervous system development, and cleft lip and palate, may be located at 4q33.     

Interstitial deletion 4q32‐34 with ulnar deficiency: 4q33 may be the critical region in 4q terminal deletion syndrome

We report on an infant with Robin sequence; mild developmental delay; a left ulnar ray defect with absent ulna and associated metacarpals, carpals and phalanges; and a right ulnar nerve hypoplasia. He had a de novo interstitial deletion of 4q32→q34. The critical region involved in the 4q terminal deletion syndrome may be 4q33. This conclusion was suggested by showing that del(4)(q31qter), del(4)(q32qter), and del(4)(q33qter) result in a similarly severe phenotype. In addition, we propose that genes for distal arm development, in particular for development of the left ulnar ray, central nervous system development, and cleft lip and palate, may be located at 4q33. © 2001 Wiley‐Liss, Inc.     

Evidence for a microdeletion in 1q32-41 involving the gene responsible for Van der Woude syndrome

Van der Woude syndrome (VWS) Is an autosomal dominant craniofacialdisorder representing the most frequent form of syndromic cleftlip and palate. Other characteristic features are pits of thelower lip and hypodontia. The gene shows high penetrance andseems to play an Important role in orofacial development determinedby the tissues involved and their formation during differentperiods of craniofacial development. Although most individualsaffected with VWS show Mendelian inheritance, one patient witha macroscopic deletion and multiple malformations Includingtwo primary features of VWS has been described In the literature(4), indicating hemizygosity Is compatible with the VWS phenotype.We report here the allelic loss of a stable and highly polymorphicmicrosatelllte (D1S205) from region 1932–41 in one familywith VWS. Classical manifestations of the syndrome superimposedon developmental delay In all affected members of the family,the absence of cytogenetic abnormalities, the reproduclbllityof the null allele with a new set of primers and close linkageof this marker in a total of 15 VWS families provide strongevidence that the first mlcrodeletion involving the gene forVWS has been identified. Assuming 1 Mb of DNA per cM of geneticdistance, the upper bound of the deletion size would amountto 4 Mb.     

A family with unusual Waardenburg syndrome type I (WSI), cleft lip (palate), and Hirschsprung disease is not linked to PAX 3

An unusual family with Waardenburg syndrome type 1 (WSI), cleft lip (palate), and Hirschsprung disease is not linked to the PAX 3 gene since there is an obligate crossover which has occurred between PAX 3 DNA markers and the disorder in this family. This family may also have anticipation of the WSI traits as the proband's grandmother is nonpenetrani, his mother has dystopia canthorum, and severe cleft lip (palate), while the proband has dystopia canthorum, severe cleft lip (palate), and Hirschsprung disease. Thus, a locus other than PAX 3 is implicated in this Waardenburg-like syndrome with Hirschsprung disease and cleft lip (palate).     

Novel lip pit phenotypes and mutations of IRF6 in Van der Woude syndrome patients from Pakistan

The role of interferon regulatory factor 6 (IRF6) gene mutations in causing Van der Woude syndrome (VWS) and poplyteal pterygium syndrome has been described in different populations worldwide. The former is one of the major syndromes of cleft lip and/or cleft palate (CL/P) with the distinct phenotype of presence of pits with or without sinuses on the lower lip. We identified seven probands with VWS from Punjab province of Pakistan and recognized two previously unreported lip pit phenotypes. The mutational analysis of IRF6 in this cohort revealed four novel and two previously reported mutations. The newly identified mutations include three frameshifts (c.635delG; c.21_33del13; c.627delC) and one transition mutation (c.2T>C) affecting the first codon of IRF6. Together with a past epidemiological study on VWS in Pakistan, the frequency of this syndrome among CL/P individuals from Punjab was calculated to be 1.17%.