Heterozygous SOX9 Mutations Allowing for Residual DNA‐binding and Transcriptional Activation Lead to the Acampomelic Variant of Campomelic Dysplasia

Campomelic dysplasia is a malformation syndrome with multiple symptoms including characteristic shortness and bowing of the long bones (campomelia). CD, often lethal due to airway malformations, is caused by heterozygous mutations in SOX9, an SRY‐related gene regulating testis and chondrocyte development including expression of many cartilage genes such as type II collagen. Male to female sex reversal occurs in the majority of affected individuals with an XY karyotype. A mild form without campomelia exists, in which sex‐reversal may be also absent. We report here two novel SOX9 missense mutations in a male (c.495C>G; p.His165Gln) and a female (c.337A>G; p.Met113Val) within the DNA‐binding domain leading to non‐lethal acampomelic CD. Functional analyses of mutant proteins demonstrate residual DNA‐binding and transactivation of SOX9‐regulated genes. Combining our data and reports from the literature we postulate a genotype‐phenotype correlation: SOX9 mutations allowing for residual function lead to a mild form of CD in which campomelia and sex reversal may be absent. © 2010 Wiley‐Liss, Inc.     

Acampomelic campomelic dysplasia: Further radiographic variations

Acampomelic campomelic dysplasia (ACD) is a rare genetic syndrome affecting bone and connective tissue. This syndrome is a variant of the more commonly encountered campomelic dysplasia but is characterized by the absence of long bone curvature (acampomelia). Affected children have a characteristically flat facial profile and present with respiratory distress. They all have markedly hypoplastic scapulae. We present two sisters with ACD between whom there were some clinical and radiographic differences and also variations from the classic CD. We describe shallow orbits, a radiographic finding that has not been previously documented in this dysplasia. Am. J. Med. Genet. 69:29–32, 1997. © 1997 Wiley-Liss, Inc.     

Acampomelic campomelic syndrome and sex reversal associated with de novo t(12;17) translocation

The association of rare chromosomal rearrangements involving a specific 17q breakpoint with campomelic syndrome (CMPS) and or sex reversal (SR) has led to an assignment of the CMPS1 SRA1 locus to 17q24.3→q25.1. We describe a patient with multiple anomalies and SR, who had a de novo t(12;17) translocation. The phenotype was consistent with that of CMPS except for the lack of lower limb bowing and talipes equinovarus. Chromosome painting indicated that the breakpoints appeared to have occurred at 12q21.32 and 17q24.3 or q25.1. This study suggests that acampomelic CMPD with SR represents a variant of the CMPS1/SRA1 locus disorder. We emphasize the likelihood that CMPS may be a contiguous gene syndrome. © 1995 Wiley-Liss, Inc.     

Two novel translocation breakpoints upstream of SOX9 define borders of the proximal and distal breakpoint cluster region in campomelic dysplasia

The semilethal skeletal malformation syndrome campomelic dysplasia (CD) with or without XY sex reversal is caused by mutations within the SOX9 gene on 17q24.3 or by chromosomal aberrations (translocations, inversions or deletions) with breakpoints outside the SOX9 coding region. The previously published CD translocation breakpoints upstream of SOX9 fall into two clusters: a proximal cluster with breakpoints between 50-300 kb and a distal cluster with breakpoints between 899-932 kb. Here, we present clinical, cytogenetic and molecular data from two novel CD translocation cases. Case 1 with karyotype 46,XY,t(1;17)(q42.1;q24.3) has characteristic symptoms of CD, including mild tibial bowing, cryptorchidism and hypospadias. By standard fluorescence in situ hybridization (FISH) and by high-resolution fiber FISH, the 17q breakpoint was mapped 375 kb from SOX9, defining the centromeric border of the proximal breakpoint cluster region. Case 2 with karyotype 46,X,t(Y;17)(q11.2;q24.3) has the acampomelic form of CD and complete XY sex reversal. By FISH and somatic cell hybrid analysis, the 17q breakpoint was mapped 789 kb from SOX9, defining the telomeric border of the distal breakpoint cluster region. We discuss the structure of the 1 Mb cis-control region upstream of SOX9 and the correlation between the position of the 14 mapped translocation breakpoints with respect to disease severity and XY sex reversal.     

A case of campomelic dysplasia without sex reversal

Campomelic dysplasia (CD; OMIM #114290), a rare form of congenital short-limbed dwarfism, is due to mutations in SOX9, a member of the SOX (SRY-related HMG box) gene family. Multiparous mother at 38 weeks' gestation delivered a 3,272 g baby boy with characteristic phenotypes including bowing of the lower limbs, a narrow thoracic cage, 11 pairs of ribs, hypoplastic scapulae, macrocephaly, flattened supraorbital ridges and nasal bridge, cleft palate, and micrognathia. He underwent a tracheostomy at the age of three months for severe laryngomalacia after a number of repeated hospitalizations due to respiratory problems and died at the age of four months from progressive respiratory failure. He was diagnosed as having CD based on a novel frameshift mutation (p.Gln458ArgfsX12) in the SOX9 gene, the mutation which has not yet been reported in Korea.     

The Most Common Mutation of KRT9, c.C487T (p.R163W), in Epidermolytic Palmoplantar Keratoderma in Two Large Chinese Pedigrees

Epidermolytic palmoplantar keratoderma (EPPK) is generally associated with dominant‐negative mutations of the Keratin 9 gene (KRT9), and rarely with the Keratin 1 gene (KRT1). To date, a myriad of mutations has been reported with a high frequency of codon 163 mutations within the first exon of KRT9 in different populations. Notably, a distinct phenotypic heterogeneity, digital mutilation, was found recently in a 58‐year‐old female Japanese EPPK patient with p.R163W. Here, we report the most common mutation, c.C487T (p.R163W) of KRT9, in two large EPPK pedigrees from southeast China. The arginine residue in peptide position 163 remains almost constant in at least 47 intermediate filament proteins ranging from snail to human. A substitution in arginine alters both the charge and shape of the 1A rod domain and disrupts the function of the helix initiation motif of keratins, finally compromising the integrity of filaments and weakening their stability in the epidermis of palms and soles. We summarize the clinical symptoms of EPPK in Chinese and show that knuckle pads are associated with KRT9 mutations. We suggest that the frequency of p.R163W in Chinese EPPK patients (31.03%) is consistent with that in the general population (29.33%), and that codon 163 is truly a hotspot mutational site of KRT9. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Familial CHARGE syndrome because of CHD7 mutation: clinical intra- and interfamilial variability

CHARGE syndrome (OMIM #214800) is a multiple malformation syndrome with distinctive diagnostic criteria, usually because of CHD7 (chromodomain helicase DNA binding 7) haploinsufficiency. Familial occurrence of CHARGE syndrome is rare. We report six patients from two Caucasian families (both with one parent and two children) affected by mild to severe CHARGE syndrome. Direct sequencing of the CHD7 gene was performed in these two unrelated families. A mutation in exon 8 (c.2501C>T - p.S834F) in first chromodomain was found in family A and a nonsense mutation in exon 2 (c.469C>T - p.R157X) in family B. Both mutations are de novo in the parents. In family A, the elder son had bilateral cleft lip and palate, esophageal atresia with fistula, complex heart defect and vertebral abnormalities, while the younger had a posterior coloboma. Their mother had asymptomatic vestibular dysfunction and retinal coloboma, identified after the molecular diagnosis of her children. In family B, both affected children had severe expression of CHARGE syndrome. The father carrying the mutation only had asymmetric anomaly of the pinnae. These familial reports describe the intrafamilial variability of CHARGE syndrome, and underline the presence of CHD7 mutations in patients who do not fit the 'classical clinical criteria' for CHARGE syndrome.     

Identification of two novel mutations in the OCRLI gene in Japanese families with Lowe syndrome

Kubota T, Sakurai A, Arakawa K, Shimazu M, Wakui K, Furihata K, Fukushima Y. Identification of two novel mutations in the OCRL1 gene in Japanese families with Lowe syndrome. Clin Genet 1998: 54: 199–202. 0 Munksgaard, 1998
The oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked disorder with features of congenital cataracts. Fanconi syndrome of the renal tubule, and mental retardation. The OCRLI gene has been positionally cloned and shown to encode a phosphatidylinositol 4.5–biphos-phate-5–phosphatase. OCRL is thus thought to be an inborn error of inositol polyphosphate metabolism. We analyzed the gene in two Japanese OCRL patients and their families by DNA sequencing and mismatch polymerase chain reaction (PCR) followed by restriction digestion. A novel nonsense mutation (C1399T) replacing the glutamine of codon 391 (Gln 391 Stop) was identified in exon 12 in 1 patient and also in his mother. A novel missense mutation (C1743G) was identified in exon 15 in the second patient, his mother and maternal grandmother. The missense mutation predicts a substitution of serine for arginine (Ser 505 Arg) in a domain highly conserved among the inosi-tol-5–phosphatase family. Our observations expand the range of OCRLI mutations that cause Lowe syndrome. and will be useful for genetic counseling in these two Fdmilies.     

Germinal mosaicism in Crouzon syndrome

Two brothers with Crouzon craniofacial dysostosis syndrome born to normal unrelated parents are described. Paternity studies show the probability of paternity is 99.6%. This report appears to represent the first example of germinal mosaicism in Crouzon syndrome.     

A chromosome 17q de novo paracentric inversion in a patient with campomelic dysplasia; case report and etiologic hypothesis

The campomelic syndrome is a skeletal dysplasia with a characteristic pattern of deformity involving the proximal and distal extremities, pelvic and shoulder girdles, thoracic cage and palate. Respiratory compromise often leads to death in early infancy. Etiology has not been determined although evidence suggests genetic heterogeneity in patients with campomelia. Cytogenetic analysis in the past have revealed an unexpectedly high incidence of a 46, XY karyotype in phenotypic females. We report here on a patient with a typical case of campomelic dysplasia in whom a de novo paracentric inversion of chromosome 17q was identified. Review of the genetic map of the inverted region identified potential "structural" genes including the Hox-2-homeobox gene and the collagen gene, COLIA1, which may be involved in the pathogenesis of campomelic syndrome.     

Identification of Novel Craniofacial Regulatory Domains Located far Upstream of SOX9 and Disrupted in Pierre Robin Sequence

Mutations in the coding sequence of SOX9 cause campomelic dysplasia (CD), a disorder of skeletal development associated with 46,XY disorders of sex development (DSDs). Translocations, deletions, and duplications within a ～2 Mb region upstream of SOX9 can recapitulate the CD–DSD phenotype fully or partially, suggesting the existence of an unusually large cis‐regulatory control region. Pierre Robin sequence (PRS) is a craniofacial disorder that is frequently an endophenotype of CD and a locus for isolated PRS at ～1.2–1.5 Mb upstream of SOX9 has been previously reported. The craniofacial regulatory potential within this locus, and within the greater genomic domain surrounding SOX9, remains poorly defined. We report two novel deletions upstream of SOX9 in families with PRS, allowing refinement of the regions harboring candidate craniofacial regulatory elements. In parallel, ChIP‐Seq for p300 binding sites in mouse craniofacial tissue led to the identification of several novel craniofacial enhancers at the SOX9 locus, which were validated in transgenic reporter mice and zebrafish. Notably, some of the functionally validated elements fall within the PRS deletions. These studies suggest that multiple noncoding elements contribute to the craniofacial regulation of SOX9 expression, and that their disruption results in PRS.     

Identification of WASP mutations in 14 Spanish families with Wiskott‐Aldrich syndrome

The Wiskott‐Aldrich syndrome (WAS) is an X‐linked immunodeficiency caused by mutations in the WASP gene. The disease is known to be associated with extensive clinical variability, and mutation studies indicate that genotypes are also highly variant among WAS patients. In this study, we performed mutation analysis of the WASP gene in 14 unrelated Spanish families by single strand conformation analysis (SSCA) and sequencing, resulting in the identification of a novel mutation and nine known mutations. No mutation was identified in one family. The ten different mutations include point mutations resulting in amino acid substitutions, stop codons, and small deletions and insertions causing frameshifts. Missense mutations were preferentially located in the amino‐terminal part of the protein, exons 2 and 4, whereas stop and frameshift mutations were located in the carboxyl‐terminal region, exons 10 and 11. However, in two families, two missense mutations in exon 11 were identified. Our study demonstrates that WASP genotypes have some concordance with the patients' phenotypes, although mutation 1019delC, identified in a family with several affected members, resulted in high intrafamilial clinical variability. © 2001 Wiley‐Liss, Inc.     

Novel mutations of the PCSK9 gene cause variable phenotype of autosomal dominant hypercholesterolemia

Autosomal dominant hypercholesterolemia (ADH) is a frequent (1/500) monogenic inherited disorder characterized by isolated elevation of LDL leading to premature cardiovascular disease. ADH is known to result from mutations at two main loci: LDLR (encoding the low density lipoprotein receptor), and APOB (encoding apolipoprotein B100), its natural ligand. We previously demonstrated that ADH is also caused by mutations of the PCSK9 (proprotein convertase subtilisin/kexin type 9) gene that encodes Narc-1 (neural apoptosis-regulated convertase 1). However, the role of this novel disease locus as a cause of hypercholesterolemia remains unclear. In the present study, we analysed the PCSK9 coding region and intronic junctions in 130 adult or pediatric patients with ADH, previously found as being non LDLR/non APOB mutation carriers. Four novel heterozygous missense variations were found: c.654A>T (p.R218S), c.1070G>A (p.R357H), c.1405C>T (p.R469W), and c.1327G>A (p.A443T). All mutations were absent in 340 normolipidemic controls. Except for the A443T, all mutations are nonconservative and modify a highly conserved residue. Segregation with hypercholesterolemia is incomplete in one pedigree. Type and severity of hyperlipidemia and of cardiovascular disease could vary among subjects from the same family. Finally, the proband carrying the R357H mutation exhibited very high plasma cholesterol during pregnancy, whereas the proband carrying the p.R469W mutation exhibited a severe phenotype of hypercholesterolemia in combination with a LDLR mutation resulting from a frameshift at residue F382 (1209delC). These observations suggest that variations in PCSK9 are a rare cause of non LDLR/non APOB ADH (approximately 2.3%) and that additional environmental or genetic factors may contribute to the phenotype caused by PCSK9 missense mutations in humans.     

男性性发育异常患者的SRY基因缺失和SOX9基因的第一外显子部分缺失分析

目的探讨SRY和SOX9基因在性发育异常基因诊断中的意义。方法染色体核型分析结合PCR扩增SRY基因和SOX9基因第一外显子。结果两病例染色体检查结果均为46,XY,未发现异常;病例1 SRY基因缺失,SOX9基因第一外显子未见异常;病例2 SRY基因未见异常,SOX9基因第一外显子部分缺失。结论 SRY基因缺失是导致病例1发病的原因,SOX9基因第一外显子部分缺失是导致病例2发病的原因。     

Vascular anomalies in campomelic syndrome

We report on 4 patients with the campomelic syndrome (CS) in whom postmortem angiography of the lower limbs was performed. Of the 4 ptients, 3 were phenotypic females (2 of them with a 46,XY karyotype) and one was a male with a normal 46,XY karyotype. Three fulfilled the criteria fo CS, and one (phenotypically female with a 46,XY karyotype) lacked the lower limb bowing and the talipes equinovarus typical of CS. This infant may constitute a further example of the recently reported CS without campomelia. The results of the angiographic study are compared with 46 postmortem angiographies of normal fetuses and newborn infants at different gestational ages. In the first 3 Cs patients the main arterial axis of the lower limb, formed by the superficial femoral and anterior tibial arteries, has smaller diameters than expected while the profunda femoris and posterior tibial arteries had greater diameters than age-matched controls However, the most striking abnormality was the absence or marked deficiency of the anterior tibial artery. Its terminal branch, the doralis pedis artery, was also absent and the plantar arch was abnormally formed by the posterior tibial artery either alone or in conjunction with the peroneal artery. The normal arterial pattern was found in the patient who lacked bowed bones. This finding supports an developmental association between vascular defects and lower limb anomalies in CS. This aberrant arterial pattern in CS may affect or be affected by muscle development. The shortness of the posterior femoral and calf muscles fix the knee and the ankle joints. Bone bowing is probably related to the abnormal mechanical forces applied to the developing long bones of the lowe limb. © 1993 Wiley-Liss, Inc.     

Tarsal‐carpal coalition syndrome: Report of a novel missense mutation in NOG gene and phenotypic delineation

We report a family of Indian origin presenting with Tarsal‐carpal coalition syndrome (TCC), which is a rare genetic disorder of skeletal abnormalities, inherited in autosomal dominant manner. In this family, three individuals (mother and two children) were found to be similarly affected with slight intrafamilial individual variability in the phenotype. Sanger sequencing revealed a novel heterozygous missense mutation in NOG gene (NM_005450.4:c.611G>A) in all the affected individuals of the family. Until now only six mutations have been reported in different families affected with TCC syndrome worldwide. This report further delineates the phenotypic spectrum of this rare disorder with the addition of a new variant to the mutation spectrum.     

Germinal mosaicism in Crouzon syndrome. A family with three affected siblings of normal parents

Germinal mosaicism is reported in three siblings with Crouzon syndrome born to normal, unrelated parents. Other probable explanations for the features in this family are discussed.