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Hale AT, Boudreau H, Devulapalli R, Duy PQ, Atchley TJ, Dewan MC, Goolam M, Fieggen G, Spader HL, Smith AA, Blount JP, Johnston JM, Rocque BG, Rozzelle CJ, Chong Z, Strahle JM, Schiff SJ, Kahle KT. The genetic basis of hydrocephalus: genes, pathways, mechanisms, and global impact. Fluids Barriers CNS 2024; 21:24. [PMID: 38439105 PMCID: PMC10913327 DOI: 10.1186/s12987-024-00513-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/25/2024] [Indexed: 03/06/2024] Open
Abstract
Hydrocephalus (HC) is a heterogenous disease characterized by alterations in cerebrospinal fluid (CSF) dynamics that may cause increased intracranial pressure. HC is a component of a wide array of genetic syndromes as well as a secondary consequence of brain injury (intraventricular hemorrhage (IVH), infection, etc.) that can present across the age spectrum, highlighting the phenotypic heterogeneity of the disease. Surgical treatments include ventricular shunting and endoscopic third ventriculostomy with or without choroid plexus cauterization, both of which are prone to failure, and no effective pharmacologic treatments for HC have been developed. Thus, there is an urgent need to understand the genetic architecture and molecular pathogenesis of HC. Without this knowledge, the development of preventive, diagnostic, and therapeutic measures is impeded. However, the genetics of HC is extraordinarily complex, based on studies of varying size, scope, and rigor. This review serves to provide a comprehensive overview of genes, pathways, mechanisms, and global impact of genetics contributing to all etiologies of HC in humans.
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Affiliation(s)
- Andrew T Hale
- Department of Neurosurgery, University of Alabama at Birmingham, FOT Suite 1060, 1720 2ndAve, Birmingham, AL, 35294, UK.
| | - Hunter Boudreau
- Department of Neurosurgery, University of Alabama at Birmingham, FOT Suite 1060, 1720 2ndAve, Birmingham, AL, 35294, UK
| | - Rishi Devulapalli
- Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Phan Q Duy
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Travis J Atchley
- Department of Neurosurgery, University of Alabama at Birmingham, FOT Suite 1060, 1720 2ndAve, Birmingham, AL, 35294, UK
| | - Michael C Dewan
- Division of Pediatric Neurosurgery, Monroe Carell Jr. Children's Hospital, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Mubeen Goolam
- Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Graham Fieggen
- Neuroscience Institute, University of Cape Town, Cape Town, South Africa
- Division of Pediatric Neurosurgery, Red Cross War Memorial Children's Hospital, University of Cape Town, Cape Town, South Africa
| | - Heather L Spader
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Anastasia A Smith
- Division of Pediatric Neurosurgery, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Jeffrey P Blount
- Division of Pediatric Neurosurgery, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, UK
| | - James M Johnston
- Division of Pediatric Neurosurgery, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Brandon G Rocque
- Division of Pediatric Neurosurgery, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Curtis J Rozzelle
- Division of Pediatric Neurosurgery, Children's of Alabama, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Zechen Chong
- Heflin Center for Genomics, University of Alabama at Birmingham, Birmingham, AL, UK
| | - Jennifer M Strahle
- Division of Pediatric Neurosurgery, St. Louis Children's Hospital, Washington University in St. Louis, St. Louis, MO, USA
| | - Steven J Schiff
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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2
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Yao H, Cai H, Li D. Thermostabilization of Membrane Proteins by Consensus Mutation: A Case Study for a Fungal Δ8-7 Sterol Isomerase. J Mol Biol 2020; 432:5162-5183. [PMID: 32105736 DOI: 10.1016/j.jmb.2020.02.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/09/2020] [Accepted: 02/12/2020] [Indexed: 11/15/2022]
Abstract
Membrane proteins are generally challenging to work with because of their notorious instability. Protein engineering has been used increasingly to thermostabilize labile membrane proteins such as G-protein-coupled receptors for structural and functional studies in recent years. Two major strategies exist. Scanning mutagenesis systematically eliminates destabilizing residues, whereas the consensus approach assembles mutants with the most frequent residues among selected homologs, bridging sequence conservation with stability. Here, we applied the consensus concept to stabilize a fungal homolog of the human sterol Δ8-7 isomerase, a 26.4 kDa protein with five transmembrane helices. The isomerase is also called emopamil-binding protein (EBP), as it binds this anti-ischemic drug with high affinity. The wild-type had an apparent melting temperature (Tm) of 35.9 °C as measured by the fluorescence-detection size-exclusion chromatography-based thermostability assay. A total of 87 consensus mutations sourced from 22 homologs gained expression level and thermostability, increasing the apparent Tm to 69.9 °C at the cost of partial function loss. Assessing the stability and activity of several systematic chimeric constructs identified a construct with an apparent Tm of 79.8 °C and two regions for function rescue. Further back-mutations of the chimeric construct in the two target regions yielded the final construct with similar apparent activity to the wild-type and an elevated Tm of 88.8 °C, totaling an increase of 52.9 °C. The consensus approach is effective and efficient because it involves fewer constructs compared with scanning mutagenesis. Our results should encourage more use of the consensus strategy for membrane protein thermostabilization.
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Affiliation(s)
- Hebang Yao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, National Center for Protein Science Shanghai, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China
| | - Hongmin Cai
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, National Center for Protein Science Shanghai, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China
| | - Dianfan Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, National Center for Protein Science Shanghai, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 333 Haike Road, Shanghai 201210, China.
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3
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Barboza-Cerda MC, Barboza-Quintana O, Martínez-Aldape G, Garza-Guajardo R, Déctor MA. Phenotypic severity in a family with MEND syndrome is directly associated with the accumulation of potentially functional variants of cholesterol homeostasis genes. Mol Genet Genomic Med 2019; 7:e931. [PMID: 31397093 PMCID: PMC6732292 DOI: 10.1002/mgg3.931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 07/23/2019] [Indexed: 11/19/2022] Open
Abstract
Background Male EBP disorder with neurologic defects (MEND) syndrome is an X‐linked disease caused by hypomorphic mutations in the EBP (emopamil‐binding protein) gene. Modifier genes may explain the clinical variability among individuals who share a primary mutation. Methods We studied four males (Patient 1 to Patient 4) exhibiting a descending degree of phenotypic severity from a family with MEND syndrome. To identify candidate modifier genes that explain the phenotypic variability, variants of homeostasis cholesterol genes identified by whole‐exome sequencing (WES) were ranked according to the predicted magnitude of their effect through an in‐house scoring system. Results Twenty‐seven from 105 missense variants found in 45 genes of the four exomes were considered significant (−5 to −9 scores). We found a direct genotype–phenotype association based on the differential accumulation of potentially functional gene variants among males. Patient 1 exhibited 17 variants, both Patients 2 and 3 exhibited nine variants, and Patient 4 exhibited only five variants. Conclusion We conclude that APOA5 (rs3135506), ABCA1 (rs9282541), and APOB (rs679899 and rs12714225) are the most relevant candidate modifier genes in this family. Relative accumulation of the deficiencies associated with variants of these genes along with other lesser deficiencies in other genes appears to explain the variable expressivity in MEND syndrome.
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Affiliation(s)
- María Carmen Barboza-Cerda
- Facultad de Medicina y Hospital Universitario "Dr. José E. González", Servicio de Anatomía Patológica y Citopatología, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico.,Facultad de Medicina y Hospital Universitario "Dr. José E. González", Departamento de Bioquímica y Medicina Molecular, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
| | - Oralia Barboza-Quintana
- Facultad de Medicina y Hospital Universitario "Dr. José E. González", Servicio de Anatomía Patológica y Citopatología, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
| | - Gerardo Martínez-Aldape
- Facultad de Medicina y Hospital Universitario "Dr. José E. González", Servicio de Anatomía Patológica y Citopatología, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
| | - Raquel Garza-Guajardo
- Facultad de Medicina y Hospital Universitario "Dr. José E. González", Servicio de Anatomía Patológica y Citopatología, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
| | - Miguel Angel Déctor
- Facultad de Medicina y Hospital Universitario "Dr. José E. González", Servicio de Anatomía Patológica y Citopatología, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico.,Facultad de Medicina y Hospital Universitario "Dr. José E. González", Departamento de Bioquímica y Medicina Molecular, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico
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4
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Horinouchi T, Morisada N, Uemura H, Kobayashi D, Nozu K, Okamoto N, Iijima K. Male CDPX2 patient with EBP mosaicism and asymmetrically lateralized skin lesions with strict midline demarcation. Am J Med Genet A 2019; 179:1315-1318. [PMID: 31034146 DOI: 10.1002/ajmg.a.61159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/17/2019] [Accepted: 03/24/2019] [Indexed: 11/10/2022]
Abstract
X-linked dominant chondrodysplasia punctata (Conradi-Hunermann-Happle syndrome, CDPX2) caused by mutations in the emopamil-binding protein (EBP) gene and congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome caused by mutation in the NAD(P)H steroid dehydrogenase-like (NSDHL) gene are rare, typically male lethal disorders. CDPX2 skin lesions are characterized by transient severe congenital ichthyosis following the lines of Blaschko, whereas in CHILD syndrome, the lesions show striking lateralization. Here, we report a male CDPX2 patient with postzygotic mosaicism of the EBP gene presenting with lateralized skin lesions with strict midline demarcation as seen in CHILD syndrome (although this diagnosis was ruled out based on analysis of NSDHL), but also partly distributed along Blaschko's lines as seen in CDPX2. The lesions resolved within a few months, but the patient had other abnormalities, including shortening of the limbs, epiphyseal stippling, and forearm asymmetry; he also had problems with respiration and feeding in the first 4 years after birth. Kyphoscoliosis with dysplastic vertebral bodies progressed rapidly and required posterior spinal fusion surgery at 6 years old. These findings provide insights into the pathophysiology of CDPX2 and the mechanism of asymmetric lesion formation during development.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Morisada
- Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
| | - Hiroyasu Uemura
- Department of Pediatrics, Japanese Red Cross Society Himeji Hospital, Hyogo, Japan
| | - Daisuke Kobayashi
- Department of Orthopaedic Surgery, Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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5
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New splicing pathogenic variant in EBP causing extreme familial variability of Conradi-Hünermann-Happle Syndrome. Eur J Hum Genet 2018; 26:1784-1790. [PMID: 30135486 DOI: 10.1038/s41431-018-0217-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/20/2018] [Accepted: 06/26/2018] [Indexed: 11/08/2022] Open
Abstract
X-linked dominant chondrodysplasia punctata (CDPX2 or Conradi-Hünermann-Happle syndrome, MIM #302960) is caused by mutations in the EBP gene. Affected female patients present with Blaschkolinear ichthyosis, coarse hair or alopecia, short stature, and normal psychomotor development. The disease is usually lethal in boys. Nevertheless, few male patients have been reported; they carry a somatic mosaicism in EBP or present with Klinefelter syndrome. Here, we report CDPX2 patients belonging to a three-generation family, carrying the splice variant c.301 + 5 G > C in intron 2 of EBP. The grandfather carries the variant as mosaic state and presents with short stature and mild ichthyosis. The mother also presents with short stature and mild ichthyosis and the female fetus with severe limb and vertebrae abnormalities and no skin lesions, with random X inactivation in both. This further characterizes the phenotypical spectrum of CDPX2, as well as intrafamilial variability, and raises the question of differential EBP mRNA splicing between the different target tissues.
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Urh K, Kolenc Ž, Hrovat M, Svet L, Dovč P, Kunej T. Molecular Mechanisms of Syndromic Cryptorchidism: Data Synthesis of 50 Studies and Visualization of Gene-Disease Network. Front Endocrinol (Lausanne) 2018; 9:425. [PMID: 30093884 PMCID: PMC6070605 DOI: 10.3389/fendo.2018.00425] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 07/09/2018] [Indexed: 12/17/2022] Open
Abstract
Background: Cryptorchidism is one of the most frequent congenital birth defects in male children and is present in 2-4% of full-term male births. It has several possible health effects including reduced fertility, increased risk for testicular neoplasia, testicular torsion, and psychological consequences. Cryptorchidism is often diagnosed as comorbid; copresent with other diseases. It is also present in clinical picture of several syndromes. However, this field has not been systematically studied. The aim of the present study was to catalog published cases of syndromes which include cryptorchidism in the clinical picture and associated genomic information. Methods: The literature was extracted from Public/Publisher MEDLINE and Web of Science databases, using the keywords including: syndrome, cryptorchidism, undescended testes, loci, and gene. The obtained data was organized in a table according to the previously proposed standardized data format. The results of the study were visually represented using Gephi and karyotype view. Results: Fifty publications had sufficient data for analysis. Literature analysis resulted in 60 genomic loci, associated with 44 syndromes that have cryptorchidism in clinical picture. Genomic loci included 38 protein-coding genes and 22 structural variations containing microdeletions and microduplications. Loci, associated with syndromic cryptorchidism are located on 16 chromosomes. Visualization of retrieved data is presented in a gene-disease network. Conclusions: The study is ongoing and further studies will be needed to develop a complete catalog with the data from upcoming publications. Additional studies will also be needed for revealing of molecular mechanisms associated with syndromic cryptorchidism and revealing complete diseasome network.
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Affiliation(s)
| | | | | | | | | | - Tanja Kunej
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
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7
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Neri G, Schwartz CE, Lubs HA, Stevenson RE. X-linked intellectual disability update 2017. Am J Med Genet A 2018; 176:1375-1388. [PMID: 29696803 DOI: 10.1002/ajmg.a.38710] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/23/2018] [Accepted: 03/23/2018] [Indexed: 12/28/2022]
Abstract
The X-chromosome comprises only about 5% of the human genome but accounts for about 15% of the genes currently known to be associated with intellectual disability. The early progress in identifying the X-linked intellectual disability (XLID)-associated genes through linkage analysis and candidate gene sequencing has been accelerated with the use of high-throughput technologies. In the 10 years since the last update, the number of genes associated with XLID has increased by 96% from 72 to 141 and duplications of all 141 XLID genes have been described, primarily through the application of high-resolution microarrays and next generation sequencing. The progress in identifying genetic and genomic alterations associated with XLID has not been matched with insights that improve the clinician's ability to form differential diagnoses, that bring into view the possibility of curative therapies for patients, or that inform scientists of the impact of the genetic alterations on cell organization and function.
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Affiliation(s)
- Giovanni Neri
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina.,Istituto di Medicina Genomica, Università Cattolica del S. Cuore, Rome, Italy
| | - Charles E Schwartz
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina
| | - Herbert A Lubs
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina
| | - Roger E Stevenson
- J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, South Carolina
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8
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Capelozza Filho L, de Almeida Cardoso M, Caldeira EJ, Capistrano A, da Silva Cordeiro A, Rocha D. Ortho-surgical management of a Conradi-Hünermann syndrome patient: rare case report. Clin Case Rep 2015; 3:694-701. [PMID: 26331015 PMCID: PMC4551328 DOI: 10.1002/ccr3.307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 03/31/2015] [Accepted: 05/12/2015] [Indexed: 11/10/2022] Open
Abstract
The Conradi-Hünermann Disease is a rare syndrome, which affects the cranial development and the anatomy of dental occlusion. After interdisciplinary treatment completion, the patient reached satisfactory facial anatomy, as well as regular occlusal relationship, attested 2 years of accompaniment.
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Affiliation(s)
- Leopoldino Capelozza Filho
- Graduation and Post Graduation Program (Specialization and MSc degrees) in Orthodontics, Sacred Heart University, USC Bauru, São Paulo, Brazil
| | - Mauricio de Almeida Cardoso
- Graduation and Post Graduation Program (Specialization and MSc degrees) in Orthodontics, Sacred Heart University, USC Bauru, São Paulo, Brazil
| | - Eduardo José Caldeira
- Department of Morphology and Basic Pathology, Faculty of Medicine of Jundiai, FMJ Jundiai, São Paulo, Brazil
| | - Anderson Capistrano
- Department of Orthodontics, Sacred Heart University USC Bauru, São Paulo, Brazil
| | | | - Diógenes Rocha
- Surgical Clinics, School of Medicine, University of São Paulo, USP São Paulo, Brazil
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9
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Radiographic features of the skeleton in disorders of post-squalene cholesterol biosynthesis. Pediatr Radiol 2015; 45:965-76. [PMID: 25646736 DOI: 10.1007/s00247-014-3257-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 11/05/2014] [Accepted: 11/26/2014] [Indexed: 01/26/2023]
Abstract
Disorders of post-squalene cholesterol biosynthesis are inborn errors of metabolism characterised by multiple congenital abnormalities, including significant skeletal involvement. The most frequent and best-characterised example is the Smith-Lemli-Opitz syndrome. Nine other disorders are known, namely autosomal-recessive Antley-Bixler syndrome, Greenberg dysplasia, X-linked dominant chondrodysplasia punctata, X-linked recessive male emopamil-binding protein deficiency, CHILD syndrome, CK syndrome, sterol C4 methyloxidase-like deficiency, desmosterolosis and lathosterolosis. This study provides an overview of the radiologic features observed in these diseases. A common pattern of limb abnormalities is recognisable, including polydactyly, which is typically post-axial and rarely interdigital and can involve all four limbs, and syndactyly of the toes. Chondrodysplasia punctata is specifically associated with a subgroup of disorders of cholesterol biosynthesis (Greenberg dysplasia, CHILD syndrome, X-linked dominant chondrodysplasia punctata, male emopamil-binding protein deficiency). The possible occurrence of epiphyseal stippling in the Smith-Lemli-Opitz syndrome, initially reported, does not appear to be confirmed. Stippling is also associated with other congenital disorders such as chromosomal abnormalities, brachytelephalangic chondrodysplasia punctata (X-linked recessive chondrodysplasia punctata, disruptions of vitamin K metabolism, maternal autoimmune diseases), rhizomelic chondrodysplasia punctata (peroxisomal disorders) and lysosomal storage disorders. In the differential diagnosis of epiphyseal stippling, a moth-eaten appearance of bones, asymmetry, or presence of a common pattern of limb abnormalities indicate inborn errors of cholesterol biosynthesis. We highlight the specific differentiating radiologic features of disorders of post-squalene cholesterol biosynthesis.
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10
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Sanchez-Pulido L, Ponting CP. TM6SF2 and MAC30, new enzyme homologs in sterol metabolism and common metabolic disease. Front Genet 2014; 5:439. [PMID: 25566323 PMCID: PMC4263179 DOI: 10.3389/fgene.2014.00439] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/27/2014] [Indexed: 12/14/2022] Open
Abstract
Carriers of the Glu167Lys coding variant in the TM6SF2 gene have recently been identified as being more susceptible to non-alcoholic fatty liver disease (NAFLD), yet exhibit lower levels of circulating lipids and hence are protected against cardiovascular disease. Despite the physiological importance of these observations, the molecular function of TM6SF2 remains unknown, and no sequence similarity with functionally characterized proteins has been identified. In order to trace its evolutionary history and to identify functional domains, we embarked on a computational protein sequence analysis of TM6SF2. We identified a new domain, the EXPERA domain, which is conserved among TM6SF, MAC30/TMEM97 and EBP (D8, D7 sterol isomerase) protein families. EBP mutations are the cause of chondrodysplasia punctata 2 X-linked dominant (CDPX2), also known as Conradi-Hünermann-Happle syndrome, a defective cholesterol biosynthesis disorder. Our analysis of evolutionary conservation among EXPERA domain-containing families and the previously suggested catalytic mechanism for the EBP enzyme, indicate that TM6SF and MAC30/TMEM97 families are both highly likely to possess, as for the EBP family, catalytic activity as sterol isomerases. This unexpected prediction of enzymatic functions for TM6SF and MAC30/TMEM97 is important because it now permits detailed experiments to investigate the function of these key proteins in various human pathologies, from cardiovascular disease to cancer.
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Affiliation(s)
- Luis Sanchez-Pulido
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
| | - Chris P Ponting
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford Oxford, UK
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11
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Shohoud SA, Azab WA, Alsheikh TM, Hegazy RM. Blake's pouch cyst and Werdnig-Hoffmann disease: Report of a new association and review of the literature. Surg Neurol Int 2014; 5:S282-8. [PMID: 25225621 PMCID: PMC4163908 DOI: 10.4103/2152-7806.139390] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 06/19/2014] [Indexed: 12/26/2022] Open
Abstract
Background: We report a case of a neonate with proximal spinal muscular atrophy (SMA) type 1 (also known as Werdnig-Hoffmann disease or severe infantile acute SMA) associated with a Blake's pouch cyst; a malformation that is currently classified within the spectrum of Dandy-Walker complex. The association of the two conditions has not been previously reported in the English literature. A comprehensive review of the pertinent literature is presented. Case Description: A male neonate was noted to have paucity of movement of the four limbs with difficulty of breathing and poor feeding soon after birth. Respiratory distress with tachypnea, necessitated endotracheal intubation and mechanical ventilation. Pregnancy was uneventful except for decreased fetal movements reported by the mother during the third trimester. Neurological examination revealed generalized hypotonia with decreased muscle power of all limbs, nonelicitable deep tendon jerks, and occasional tongue fasciculations. Molecular genetic evaluation revealed a homozygous deletion of both exons 7 and 8 of the survival motor neuron 1 (SMN1) gene, and exon 5 of the neuronal apoptosis inhibitory protein (NAIP) gene on the long arm of chromosome 5 consistent with Werdnig-Hoffmann disease (SMA type 1). At the age of 5 months, a full anterior fontanelle and abnormal increase of the occipito-frontal circumference were noted. Computed tomographic (CT) scan and magnetic resonance imaging (MRI) of the brain revealed a tetraventricular hydrocephalus and features of Blake's pouch cyst of the fourth ventricle. Conclusions: This case represents a previously unreported association of Blake's pouch cyst and SMA type 1.
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Affiliation(s)
- Sherien A Shohoud
- Neonatal Intensive Care Unit, Ibn Sina Hospital, Kuwait City, Kuwait
| | - Waleed A Azab
- Department of Neurosurgery, Ibn Sina Hospital, Kuwait City, Kuwait
| | - Tarek M Alsheikh
- Department of Neurosurgery, Ibn Sina Hospital, Kuwait City, Kuwait
| | - Rania M Hegazy
- Department of Diagnostic Radiology, Jahra Hospital, Kuwait City, Kuwait
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12
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Lambrecht C, Wouters C, Van Esch H, Moens P, Casteels I, Morren MA. Conradi-Hünermann-Happle syndrome: a novel heterozygous missense mutation, c.204G>T (p.W68C). Pediatr Dermatol 2014; 31:493-6. [PMID: 24915996 DOI: 10.1111/pde.12336] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Conradi-Hünermann-Happle syndrome (X-linked dominant chondrodysplasia punctata, CDPX2 [Online Mendelian Inheritance in Man 302960]) is a rare genodermatosis that presents with blaschkolinear ichthyosis, cicatricial alopecia, chondrodysplasia punctata, asymmetric shortening of the bones, and cataracts. In this case report we describe a child presenting with a patterned alopecia in which supplementary signs and clinical examination of the mother led to the suspicion of Conradi-Hünermann-Happle syndrome. Mutation analysis revealed a heterozygous novel missense mutation, c.204G>T (p.W68C), in exon 2.
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13
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Barboza-Cerda MC, Wong LJ, Martínez-de-Villarreal LE, Zhang VW, Déctor MA. A novel EBP c.224T>A mutation supports the existence of a male-specific disorder independent of CDPX2. Am J Med Genet A 2014; 164A:1642-7. [PMID: 24700572 DOI: 10.1002/ajmg.a.36508] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/31/2014] [Indexed: 11/08/2022]
Abstract
Mutations in the Emopamil-binding protein (EBP) gene cause X-linked dominant chondrodysplasia punctata 2 (CDPX2), a disorder in which at least 95% of liveborn individuals are female and male intrauterine lethality is assumed. Several affected males with mutations in EBP have been reported. These males exhibit a phenotype similar to CDPX2 due to either somatic mosaicism or a 47, XXY karyotype in association with a null EBP allele. Alternatively, affected males may exhibit a distinct phenotype if they are hemizygous for a hypomorphic allele of EBP. Recently, we described a novel X-linked phenotype associated with digital abnormalities, intellectual disability and short stature, and mapped it to Xp11.4-p11.21. X-exome sequencing was performed to identify the mutated gene responsible for this phenotype. A novel missense variant, c.224T>A (p.I75N), was identified in EBP. SIFT and PolyPhen-2 predicted this change to be deleterious. The pathogenicity of this variant was subsequently supported by increased plasma levels of 8(9)-cholestenol in the proband and his mother. The molecular and biochemical evidence convincingly supports the pathogenicity and association of the p.I75N mutation with this newly described phenotype. This study expands the current phenotypic spectrum of males with hypomorphic EBP mutations and supports to the hypothesis that there exists an X-linked recessive entity independent of CDPX2.
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Affiliation(s)
- María C Barboza-Cerda
- Departamento de Genética, Facultad de Medicina y Hospital Universitario "José E. González", Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México
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Hartill VL, Tysoe C, Manning N, Dobbie A, Santra S, Walter J, Caswell R, Koster J, Waterham H, Hobson E. An unusual phenotype of X-linked developmental delay and extreme behavioral difficulties associated with a mutation in the EBP gene. Am J Med Genet A 2014; 164A:907-14. [PMID: 24459067 DOI: 10.1002/ajmg.a.36368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 10/28/2013] [Indexed: 11/11/2022]
Abstract
We report on a family in which four males over three generations are affected with X-linked recessive developmental delay, learning difficulties, severe behavioral difficulties and mild dysmorphic features. Plasma sterol analysis in three of the four affected males demonstrated increased concentrations of 8-dehydrocholesterol (8-DHC) and cholest-8(9)-enol. All four affected males had a novel hemizygous missense mutation, p.W47R (c.139T>C), in EBP. Functional studies showed raised levels of cholest-8(9)-enol in patient's cultured fibroblast cells, which were suppressed when the cells were incubated with simvastatin. EBP encodes 3β-hydroxysteroid-delta8, delta7-isomerase, a key enzyme involved in the cholesterol biosynthesis pathway. Mutations in EBP have previously been associated with Conradi-Hunermann-Happle syndrome (CHH), an X-linked dominant disorder characterized by skeletal dysplasia, skin, and ocular abnormalities, which is usually lethal in males. Four previous reports describe X-linked recessive multiple anomaly syndromes associated with non-mosaic EBP mutations in males, two at the same amino acid position, p.W47C. This phenotype has previously been described as "MEND" syndrome (male EBP disorder with neurological defects). The family reported herein represent either a novel phenotype, or an expansion of the MEND phenotype, characterized by extreme behavioral difficulties and a scarcity of structural anomalies. Simvastatin therapy is being evaluated in two males from this family.
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Affiliation(s)
- Verity L Hartill
- Yorkshire Regional Genetics Service, Chapel Allerton Hospital, Leeds, UK
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Cañueto J, Girós M, González-Sarmiento R. The role of the abnormalities in the distal pathway of cholesterol biosynthesis in the Conradi-Hünermann-Happle syndrome. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:336-44. [PMID: 24036494 DOI: 10.1016/j.bbalip.2013.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 11/28/2022]
Abstract
Conradi-Hünermann-Happle syndrome (CDPX2, OMIM 302960) is an inherited X-linked dominant variant of chondrodysplasia punctata (CP) caused by mutations in one gene of the distal pathway of cholesterol biosynthesis. It exhibits intense phenotypic variation and primarily affects the skin, bones and eyes. The ichthyosis following Blaschko's lines, chondrodysplasia punctata and cataracts are the typical clinical findings. The cardinal biochemical features are an increase in 8(9)-cholestenol and 8-dehydrocholesterol (8DHC), which suggest a deficiency in 3β-hydroxysteroid-Δ8,Δ7-isomerase, also called emopamil binding protein (EBP). The EBP gene is located on the short arm of the X chromosome (Xp11.22-p11.23) and encodes a 230 amino acid protein with dual function. Explaining the clinical phenotype in CDPX2 implies an understanding of both the genetics and biochemical features of this disease. CDPX2 displays an X-linked dominant pattern of inheritance, which is responsible for the distribution of lesions in some tissues. The clinical phenotype in CDPX2 results directly from impairment in cholesterol biosynthesis, and indirectly from abnormalities in the hedgehog signaling protein pathways. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Javier Cañueto
- Department of Dermatology, University Hospital of Salamanca, Paseo San Vicente 58-182, 37007 Salamanca, Spain; IBSAL (Instituto de Investigación Biosanitaria de Salamanca), Spain.
| | - Marisa Girós
- Seccio Errors Congenits del Metabolisme, Servei de Bioquímica Clínica i Genética Molecular, Hospital Clinic Barcelona, Barcelona, Spain
| | - Rogelio González-Sarmiento
- IBSAL (Instituto de Investigación Biosanitaria de Salamanca), Spain; Molecular Medicine Unit, Faculty of Medicine, University of Salamanca, Campus Miguel de Unamuno S/N, Salamanca 37007, Spain; Laboratory 14, IBMCC-CSIC, University of Salamanca, Campus Miguel de Unamuno S/N, Salamanca 37007, Spain
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Cayce R, Word AP, Agim N, Yancey KB. Pattern ichthyosis in a newborn. Pediatr Dermatol 2013; 30:621. [PMID: 24016287 DOI: 10.1111/j.1525-1470.2012.01792.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Rachael Cayce
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas
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Bode H, Galm C, Hummler H, Teller C, Haas D, Gencik M. Non-lethal non-mosaic male with Conradi-Hunermann syndrome caused by a novel EBP c.356T>G mutation. Am J Med Genet A 2013; 161A:2385-8. [PMID: 23852825 DOI: 10.1002/ajmg.a.35985] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 03/13/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Harald Bode
- Division of Social Pediatrics and Child Neurology, University Childrens's Hospital, Frauensteige 10, D-89077 Ulm, Germany.
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Abstract
Genetic mosaicism is defined as the existence of at least two genetically distinct cell populations within one individual. Mosaic presentation of genetic disorders is common and is often particularly obvious in the skin, because there it will generate recognizable patterns. Recognizing those can frequently assist in establishing a diagnosis. In this review, we discuss the mechanisms that give rise to genetic mosaicism. We describe its most frequent cutaneous manifestations that are relevant to paediatric practice. While most mosaic genetic diseases are rare, it is important to recognize them so that patients and parents may receive appropriate genetic counselling. Moreover, recent developments are now resulting in novel, targeted treatments for such disorders that promise to considerably improve patients' lives.
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Herman GE, Kratz L. Disorders of sterol synthesis: beyond Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:301-21. [PMID: 23042573 DOI: 10.1002/ajmg.c.31340] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since the discovery in 1993 that Smith-Lemli-Opitz syndrome (SLOS) is a disorder of cholesterol biosynthesis, human disorders associated with additional enzymes involved in the conversion of lanosterol to cholesterol have been identified. This review will focus primarily on the clinical aspects of these disorders, highlighting newly described syndromes, such as SC4MOL deficiency and CK syndrome. We will also provide clinical descriptions of additional cases for extremely rare disorders, such as desmosterolosis. We will compare and contrast the findings with those found in SLOS and briefly discuss possible mechanisms of disease pathogenesis.
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Affiliation(s)
- Gail E Herman
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, 700 Children's Dr. Rm W403, Columbus, OH 43205, USA.
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Arnold AW, Bruckner-Tuderman L, Has C, Happle R. Conradi-Hünermann-Happle syndrome in males vs. MEND syndrome (male EBP disorder with neurological defects). Br J Dermatol 2012; 166:1309-13. [PMID: 22229330 DOI: 10.1111/j.1365-2133.2012.10808.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND There is confusion in the literature concerning disorders caused by EBP (emopamil-binding protein) mutations in males. OBJECTIVES To study the clinical and genetic differences in males affected either with Conradi-Hünermann-Happle (CHH) syndrome (X-linked dominant chondrodysplasia punctata, CDPX2) or with a nonmosaic, X-linked recessive disorder for which we propose the acronymic term MEND syndrome (male EBP disorder with neurological defects). METHODS We report a 7-year-old boy with a history of transient scaly erythematous lesions on his limbs, trunk and scalp soon after birth. DNA was isolated from ethylenediamine tetraacetic acid-blood samples of the patient and the four coding exons of the EBP gene were amplified by polymerase chain reaction. We review all published cases of CHH syndrome in males in the literature and elaborate the clinical and genetic differences between CHH syndrome in males and MEND syndrome. RESULTS We found at position 33 of the EBP gene the variant c.33C>A leading to the same nonsense mutation p.Y11X that had previously occurred de novo in a female with typical manifestations of CHH syndrome. When the known male cases with EBP mutations were reviewed, a striking nosological difference between the mosaic and nonmosaic phenotypes was evident. Clear-cut clinical criteria are elaborated to distinguish between CHH syndrome in males and MEND syndrome. CONCLUSIONS Because the clinical outcome and prognosis are different it is important to distinguish between males with CHH syndrome that represents a mosaic phenotype, and those with MEND syndrome that is a nonmosaic trait.
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Affiliation(s)
- A W Arnold
- Department of Dermatology, Freiburg University Medical Center, 79104 Freiburg, Germany.
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Rope AF, Carey JC. Response to Happle a novel X linked phenotype caused by hypomorphic EBP mutation. Am J Med Genet A 2011. [DOI: 10.1002/ajmg.a.34089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Happle R. A novel X-linked phenotype caused by hypomorphic EBP mutations. Am J Med Genet A 2011; 155A:1770-1; author reply 1772. [PMID: 21465663 DOI: 10.1002/ajmg.a.33988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 02/14/2011] [Indexed: 11/09/2022]
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