Biallelic mutations in DYNC2LI1 are a rare cause of Ellis‐van Creveld syndrome

Ellis‐van Creveld syndrome (EvC) is a chondral and ectodermal dysplasia caused by biallelic mutations in the EVC, EVC2 and WDR35 genes. A proportion of cases with clinical diagnosis of EvC, however, do not carry mutations in these genes. To identify the genetic cause of EvC in a cohort of mutation‐negative patients, exome sequencing was undertaken in a family with 3 affected members, and mutation scanning of a panel of clinically and functionally relevant genes was performed in 24 additional subjects with features fitting/overlapping EvC. Compound heterozygosity for the c.2T>C (p.Met1?) and c.662C>T (p.Thr221Ile) variants in DYNC2LI1, which encodes a component of the intraflagellar transport‐related dynein‐2 complex previously found mutated in other short‐rib thoracic dysplasias, was identified in the 3 affected members of the first family. Targeted resequencing detected compound heterozygosity for the same missense variant and a truncating change (p.Val141*) in 2 siblings with EvC from a second family, while a newborn with a more severe phenotype carried 2 DYNC2LI1 truncating variants. Our findings indicate that DYNC2LI1 mutations are associated with a wider clinical spectrum than previously appreciated, including EvC, with the severity of the phenotype likely depending on the extent of defective DYNC2LI1 function.     

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.     

Ellis Van Creveld2 is Required for Postnatal Craniofacial Bone Development

Ellis‐van Creveld (EvC) syndrome is a genetic disorder with mutations in either EVC or EVC2 gene. Previous case studies reported that EvC patients underwent orthodontic treatment, suggesting the presence of craniofacial bone phenotypes. To investigate whether a mutation in EVC2 gene causes a craniofacial bone phenotype, Evc2 knockout (KO) mice were generated and cephalometric analysis was performed. The heads of wild type (WT), heterozygous (Het) and homozygous Evc2 KO mice (1‐, 3‐, and 6‐week‐old) were prepared and cephalometric analysis based on the selected reference points on lateral X‐ray radiographs was performed. The linear and angular bone measurements were then calculated, compared between WT, Het and KO and statistically analyzed at each time point. Our data showed that length of craniofacial bones in KO was significantly lowered by ～20% to that of WT and Het, the growth of certain bones, including nasal bone, palatal length, and premaxilla was more affected in KO, and the reduction in these bone length was more significantly enhanced at later postnatal time points (3 and 6 weeks) than early time point (1 week). Furthermore, bone‐to‐bone relationship to cranial base and cranial vault in KO was remarkably changed, i.e. cranial vault and nasal bone were depressed and premaxilla and mandible were developed in a more ventral direction. Our study was the first to show the cause‐effect relationship between Evc2 deficiency and craniofacial defects in EvC syndrome, demonstrating that Evc2 is required for craniofacial bone development and its deficiency leads to specific facial bone growth defect. Anat Rec, 299:1110–1120, 2016. © 2016 Wiley Periodicals, Inc.     

Long interspersed nuclear element-1 (LINE1)-mediated deletion of EVC, EVC2, C4orf6, and STK32B in Ellis-van Creveld syndrome with borderline intelligence

Previous work has shown Ellis-van Creveld (EvC) patients with mutations either in both alleles of EVC or in both alleles of EVC2. We now report affected individuals with the two genes inactivated on each allele. In a consanguineous pedigree diagnosed with EvC and borderline intelligence, we detected a 520-kb homozygous deletion comprising EVC, EVC2, C4orf6, and STK32B, caused by recombination between long interspersed nuclear element-1 (LINE-1 or L1) elements. Patients homozygous for the deletion are deficient in EVC and EVC2 and have no increase in the severity of the EvC typical features. Similarly deletion carriers demonstrate absence of digenic inheritance in EvC. Further, the phenotype of these patients suggests that the EVC-STK32B deletion also leads to mild mental retardation and reveals that loss of the novel genes C4orf6 and STK32B causes at most mild mental deficit. In an EvC compound heterozygote of different ethnic origin we identified the same LINE-to-LINE rearrangement due to a different recombination event. These findings highlight the importance of L1 repetitive sequences in human genome architecture and disease.     

The Role of Ellis‐Van Creveld 2(EVC2) in Mice During Cranial Bone Development

EvC syndrome is a type of autosomal‐recessive chondrodysplasia. Previous case studies in patients suggest abnormal craniofacial development, in addition to dwarfism and tooth abnormalities. To investigate how craniofacial development is affected in EvC patients, surface models were generated from micro‐CT scans of control mice, Evc2 global mutant mice and Evc2 neural crest‐specific mutant mice. The anatomic landmarks were placed on the surface model to assess the morphological abnormalities in the Evc2 mutants. Through analyzing the linear and angular measurements between landmarks, we identified a smaller overall skull, shorter nasal bone, shorter frontal bone, and shorter cranial base in the Evc2 global mutants. By comparing neural crest‐specific Evc2 mutants with control mice, we demonstrated that the abnormalities within the mid‐facial regions are not accounted for by the Evc2 mutation within these regions. Additionally, we also identified disproportionate length to width ratios in the Evc2 mutants at all levels from anterior to posterior of the skull. Overall, this study demonstrates a more comprehensive analysis on the craniofacial morphological abnormalities in EvC syndrome and provides the developmental insight to appreciate the impact of Evc2 mutation within the neural crest cells on multiple aspects of skull deformities. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:46–55, 2018. © 2017 Wiley Periodicals, Inc.     

Schuurs‐Hoeijmakers syndrome in a patient from India

Schuurs‐Hoeijmakers syndrome (SHMS), or Autosomal Dominant Mental Retardation Syndrome type 17 (MRD17) is a rare form of intellectual disability with distinct facial features. A recurrent de novo heterozygous c.607C>T, p.Arg203Trp mutation in the PACS1 gene accounts for all reported cases except for one patient with a de novo heterozygous c.608G>A, p.Arg203Trp mutation. Ethnic background is known to affect the clinical manifestation of dysmorphic syndromes. Here we describe the first Indian patient with Schuurs‐Hoeijmakers syndrome (SHMS) with a de novo heterozygous NM_018026.3 (PACS1):c.607C>T (p.Arg203Trp) variant. He is the only child with SHMS with a cleft lip. Thus our report expands the phenotypic spectrum of SHMS and establishes its occurrence across populations.     

Cleft palate and hypopituitarism in a patient with Noonan‐like syndrome with loose anagen hair‐1

Noonan syndrome (NS), the most common of the RASopathies, is a developmental disorder caused by heterozygous germline mutations in genes encoding proteins in the RAS‐MAPK signaling pathway. Noonan‐like syndrome with loose anagen hair (NSLH, including NSLH1, OMIM #607721 and NSLH2, OMIM #617506) is characterized by typical features of NS with additional findings of macrocephaly, loose anagen hair, growth hormone deficiency in some, and a higher incidence of intellectual disability. All NSLH1 reported cases to date have had an SHOC2 c.4A>G, p.Ser2Gly mutation; NSLH2 cases have been reported with a PPP1CB c.146G>C, p.Pro49Arg mutation, or c.166G>C, p.Ala56Pro mutation. True cleft palate does not appear to have been previously reported in individuals with NS or with NSLH. While some patients with NS have had growth hormone deficiency (GHD), other endocrine abnormalities are only rarely documented. We present a female patient with NSLH1 who was born with a posterior cleft palate, micrognathia, and mild hypotonia. Other findings in her childhood and young adulthood years include hearing loss, strabismus, and hypopituitarism with growth hormone, thyroid stimulating hormone (TSH), and gonadotropin deficiencies. The SHOC2 mutation may be responsible for this patient's additional features of cleft palate and hypopituitarism.     

RAF1 variant in a patient with Noonan syndrome with multiple lentigines and craniosynostosis

We report the case of a 14 years and 8 months girl, who is the first child of nonconsanguineous parents, with short stature, obstructive hypertrophic cardiomyopathy, multiple facial lentigines, high and wide forehead, downslanting palpebral fissures, low‐set ears, short neck, and pectus excavatum; all features suggestive of Noonan syndrome with multiple lentigines (NSML). In addition, the patient exhibited craniosynostosis. Molecular analysis of rats sarcoma (RAS)/mitogen‐activated protein kinase (MAPK) pathway genes with high‐resolution melting curve analysis followed by sequencing showed a RAF1 amino acid substitution of valine to glycine at position 263 (p.V263G). The present report provides clinical data regarding the first association of a RAF1 variant and craniosynostosis in a patient with clinical diagnosis of NSML.     

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.     

A case of severe TBCE‐negative hypoparathyroidism‐retardation‐dysmorphism syndrome: Case report and literature review

Hypoparathyroidism‐retardation‐dysmorphism syndrome (HRD) is a rare autosomal recessive disorder attributed to the mutations in the tubulin‐specific chaperone E (TBCE) gene, which is vital for microtubule function during mitosis, organelle positioning, and neuronal cytokinesis. HRD is a congenital syndromic hypoparathyroidism associated with growth deficiency, microcephaly, intellectual disability, ocular anomalies, and facial dysmorphism. To our knowledge, there is only one published case of mild HRD‐like syndrome with no identifiable genetic etiology. We report a case of severe TBCE‐negative phenotypic HRD in a 4‐year‐old female from India presenting with hypocalcemic seizures due to congenital hypoparathyroidism, extreme microcephaly, growth deficiency, ocular anomalies, and facial dysmorphism. SNP microarray and whole exome sequencing (WES) did not detect any abnormalities in TBCE or other genes of interest. WES revealed two variants of unknown clinical significance in CASC5 gene, which codes for a protein in the kinetochore and, interestingly similar to TBCE, is essential for proper microtubule function during mitosis and cell proliferation and has been implicated in primary microcephaly disorders. However, further targeted sequencing in the parents revealed both variants inherited from the unaffected mother. Significant copy number variant noise in the proband and her parents limited further analysis. At this time the role of variants in the CASC5 gene is unclear and cannot explain our patient's phenotype. In conclusion, we report a severe case of phenotypic HRD syndrome, in which extensive genetic evaluation failed to reveal an etiology. Our case demonstrates that the pathogenesis of HRD may be genetically heterogenous, meriting further genetic investigations.     

Cole‐Carpenter syndrome in a patient from Thailand

Cole‐Carpenter syndrome (CCS), commonly classified as a rare type of osteogenesis imperfecta, is a disorder with severe bone fragility, craniosynostosis, and distinct facial features. Recently, the heterozygous missense mutation, c.1178A>G, p.Tyr393Cys, in exon 9 of P4HB which encodes protein disulfide isomerase, has been found in three Caucasian patients with CCS. Ethnic background is known to affect clinical manifestations, especially facial features of dysmorphic syndromes. Here, we describe the first Asian CCS patient possessing the recurrent mutation in P4HB. Although she had several common features of CCS including bulging forehead, ocular proptosis, midface hypoplasia, long bone deformity, popcorn epiphyses, vertebral fractures, and scoliosis, she did not have hydrocephalus, wormian bones, and dentinogenesis imperfecta, commonly seen in Caucasian patients. Interestingly, she is the only one without macrocephaly. Radiologically, metadiaphyseal fractures of the long bones with metaphyseal sclerosis were found, substantiating that they provide a definitive radiological feature of CCS. In addition, we showed for the first time a three‐dimensional facial scan of a patient with CCS. She had been given intravenous bisphosphonate since the age of 9 months and had responded well. Our study presents the clinical features of the first Asian patient, supports metaphyseal scleroses and fractures as radiological clues, strengthens early bisphosphonate administration, and confirms the etiologic role of the c.1178A>G variant in P4HB across populations.     

Refinement and delineation of the breakpoint regions of a chromosome 1;22 translocation in a patient with Costello syndrome*

Altered plasma levels of lipids and lipoproteins, obesity, hypertension, and diabetes are major risk factors for atherosclerotic cardiovascular disease. To identify genes that affect these traits and disorders, we looked for association between markers in candidate genes (apolipoprotein AII (apo AII), apolipoprotein AI‐CIII‐AIV gene cluster (apo AI‐CIII‐AIV), apolipoprotein E (apo E), cholesteryl ester transfer protein (CETP), cholesterol 7α‐hydroxylase (CYP7a), hepatic lipase (HL), and microsomal triglyceride transfer protein (MTP)) and known risk factors (triglycerides (Tg), total cholesterol (TC), apolipoprotein AI (apo AI), apolipoprotein AII (apo AII), apolipoprotein B (apo B), body mass index (BMI), blood pressure (BP), leptin, and fasting blood sugar (FBS) levels.) A total of 1,102 individuals from the Pacific island of Kosrae were genotyped for the following markers: Apo AII/MspI, Apo CIII/SstI, Apo AI/XmnI, Apo E/HhaI, CETP/TaqIB, CYP7a/BsaI, HL/DraI, and MTP/HhpI. After testing for population stratification, family‐based association analysis was carried out. Novel associations found were: 1) the apo AII/MspI with apo AI and BP levels, 2) the CYP7a/BsaI with apo AI and BMI levels. We also confirmed the following associations: 1) the apo AII/MspI with Tg level; 2) the apo CIII/SstI with Tg, TC, and apo B levels; 3) the Apo E/HhaI E2, E3, and E4 alleles with TC, apo AI, and apo B levels; and 4) the CETP/TaqIB with apo AI level. We further confirmed the connection between the apo AII gene and Tg level by a nonparametric linkage analysis. We therefore conclude that many of these candidate genes may play a significant role in susceptibility to heart disease. © 2002 Wiley‐Liss, Inc.     

ADA2 deficiency in a patient with Noonan syndrome‐like disorder with loose anagen hair: The co‐occurrence of two rare syndromes

Noonan syndrome‐like disorder with loose anagen hair (NS/LAH) is one of the RASopathies, a group of clinically related developmental disorders caused by germline mutations in genes that encode components acting in the RAS/MAPK pathway. Among RASopathies, NS/LAH (OMIM 607721) is an extremely rare, multiple anomaly syndrome characterized by dysmorphic facial features similar to those observed in Noonan syndrome along with some distinctive ectodermal findings including easily pluckable, sparse, thin, and slow‐growing hair. ADA2 deficiency (DADA2, OMIM 615688) is a monogenic autoinflammatory disorder caused by homozygous or compound heterozygous mutations in ADA2, with clinical features including recurrent fever, livedo racemosa, hepatosplenomegaly, and strokes as well as immune dysregulation. This is the first report of NS/LAH and ADA2 deficiency in the same individual. We report on a patient presenting with facial features, recurrent infections and ectodermal findings in whom both the clinical and molecular diagnoses of NS/LAH and ADA2 deficiency were established, respectively.     

SOFT syndrome in a patient from Chile

SOFT syndrome (MIM614813) is an extremely rare primordial dwarfism caused by biallelic mutations in the POC1A gene. It is characterized by prenatal short stature, onychodysplasia, facial dysmorphism, hypotrichosis, and variable skeletal abnormalities including hypoplastic pelvis and sacrum, small hands, and cone‐shaped epiphyses, as well as delayed bone age. To the best of our knowledge, only eight POC1A mutations have been reported in humans to date. We report a 7‐year‐old Chilean girl with SOFT syndrome arising from a novel POC1A mutation c. 649C>T, p.Arg217Trp. Although her clinical features were largely compatible with SOFT syndrome, hand X‐ray examinations at 3.5 and 6 years unexpectedly showed normal bone age. Automated bone age determination was performed using image analysis software, BoneXpert. This case highlights the importance of the accumulation of patients with POC1A mutations to further elucidate the detailed clinical features of SOFT syndrome.     

MECP2 duplication syndrome in a patient from Cameroon

MECP2 duplication syndrome (MDS; OMIM 300260) is an X‐linked neurodevelopmental disorder caused by nonrecurrent duplications of the Xq28 region involving the gene methyl‐CpG‐binding protein 2 (MECP2; OMIM 300005). The core phenotype of affected individuals includes infantile hypotonia, severe intellectual disability, very poor‐to‐absent speech, progressive spasticity, seizures, and recurrent infections. The condition is 100% penetrant in males, with observed variability in phenotypic expression within and between families. Features of MDS in individuals of African descent are not well known. Here, we describe a male patient from Cameroon, with MDS caused by an inherited 610 kb microduplication of Xq28 encompassing the genes MECP2, IRAK1, L1CAM, and SLC6A8. This report supplements the public data on MDS and contributes by highlighting the phenotype of this condition in affected individuals of African descent.     

Wiedemann‐Steiner syndrome in two patients from Portugal

Wiedemann‐Steiner syndrome (WSS) is a rare genetic disorder characterized by growth retardation, facial dysmorphism, hypertrichosis cubiti and neurodevelopment delay. It is caused by pathogenic variants in the KMT2A gene. This report describes two unrelated Portuguese patients, age 11 and 17 years, with a phenotype concordant with WSS and clinical and molecular diagnosis of WSS by the identification of two novel frameshift variants in the KMT2A gene. This work also highlights the presence of certain clinical features in patients with growth retardation and development delay and should draw attention to the diagnosis of WSS, when hirsutism, particularly hypertrichosis cubiti is present.     

Concomitant and noncanonical JAK2 and MPL mutations in JAK2V617F‐ and MPLW515 L‐positive myelofibrosis

Sequential genotyping for phenotype‐driver mutations in JAK2 (exon 14), CALR (exon 9), and MPL (exon 10) is recommended in patients with myeloproliferative neoplasms. Yet, atypical JAK2‐ and MPL‐mutations were described in some triple‐negative patients. Whether noncanonical and/or concomitant JAK2‐ and MPL‐mutations exist in myelofibrosis (MF) regardless of phenotype‐driver mutations is not yet elucidated. For this, next‐generation sequencing (NGS) was performed using blood genomic DNA from 128 MF patients (primary MF, n = 93; post‐ET–MF, n = 18; post‐PV–MF, n = 17). While no atypical JAK2‐ or MPL‐mutations were seen in 24 CALR‐positive samples, two JAK2‐mutations [c.3323A > G, p.N1108S; c.3188G > A, p.R1063H] were detected in two of the 21 (9.5%) triple‐negative patients. Twelve of the 82 (14.6%) JAK2V617F‐positive cases had coexisting germline JAK2‐mutations [JAK2R1063H, n = 6; JAK2R893T, n = 1; JAK2T525A, n = 1] or at least one somatic MPL‐mutation [MPLY591D, n = 3; MPLW515 L, n = 2; MPLE335K, n = 1]. Overall, MPL‐mutations always coexisted with JAK2V617F and/or other MPL‐mutations. None of the JAK2V617F plus a second JAK2‐mutation carried a TET2‐mutation but all patients with JAK2V617F plus an MPL‐mutation harbored a somatic TET2‐mutation. Four genomic clusters could be identified in the JAK2V617F‐positive cohort. Cluster‐I (10%) (noncanonical JAK2_{mutated (mut)} + TET2_{wildtype (wt)}) were younger and had less proliferative disease compared with cluster‐IV (5%) (TET2_mut + MPL_mut). In conclusion, recurrent concomitant classical and/or noncanonical JAK2‐ and MPL‐mutations could be detected by NGS in 15.7% of JAK2V617F‐ and MPLW515‐positive MF patients with genotype‐phenotype associations. Many of the germline and/or somatic mutations might act as “Significantly Mutated Genes” contributing to the pathogenesis and phenotypic heterogeneity. A cost‐effective NGS‐based approach might be an important step towards patient‐tailored medicine.     

Saethre‐Chotzen syndrome and hyper IgE syndrome in a patient with a novel 11 bp deletion of the TWIST gene

Molecular genetic studies in a seven‐year‐old boy and his mother demonstrated a novel 11 bp deletion in the TWIST gene (127del11), causing Saethre‐Chotzen syndrome. The mother had rather mild signs of the Saethre‐Chotzen syndrome; however, her son presented with marked acrocephalosyndactyly type 3, leading to craniotomy at three years. He also had recurrent infections and laboratory findings comparable with the hyper IgE syndrome, a rare primary immunodeficiency disorder. It is likely that the 11bp deletion caused the Saethre‐Chotzen syndrome in the patient and his mother, and another, not yet identified genetic defect, seen in the patient but not in the mother, is responsible for the hyper IgE phenotype. A combination of these two congenital conditions has not been described to date. © 2001 Wiley‐Liss, Inc.