1
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Villalba MF, Li CM, Pakravan P, Bademci G, Chang TCP. Commercial Gene Panels for Congenital Anterior Segment Anomalies: Are They All the Same? Am J Ophthalmol 2023; 251:90-103. [PMID: 36906093 PMCID: PMC10247492 DOI: 10.1016/j.ajo.2023.02.025] [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: 09/04/2022] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/11/2023]
Abstract
PURPOSE We compared next generation sequencing multigene panels (NGS-MGP) from 5 commercial laboratories to inform ophthalmologists' decision making in diagnostic genetic testing for congenital anterior segment anomalies (CASAs). DESIGN Comparison of commercial genetic testing panels. METHODS This observational study gathered publicly available information on NGS-MGP from 5 commercial laboratories for the following: cataracts, glaucoma, anterior segment dysgenesis (ASD), microphthalmia-anophthalmia-coloboma (MAC), corneal dystrophies, and Axenfeld-Rieger syndrome (ARS). We compared gene panel composition, consensus rate (genes covered by all the panels per condition, "concurrent"), dissensus rate (genes covered by only 1 panel per condition, "standalone"), and intronic variant coverage. For individual genes, we compared publication history and association with systemic conditions. RESULTS Altogether, cataract, glaucoma, corneal dystrophies, MAC, ASD, and ARS panels tested 239, 60, 36, 292, and 10 discrete genes, respectively. The consensus rate varied between 16% and 50%, and the dissensus rate varied between 14% and 74%. After pooling concurrent genes from all conditions, 20% of these genes were concurrent in 2 or more conditions. For both cataract and glaucoma, concurrent genes had significantly stronger correlation with the condition than standalone genes. CONCLUSIONS The genetic testing of CASAs using NGS-MGPs is complicated, owing to their number, variety, and phenotypic and genetic overlap. Although the inclusion of additional genes, such as the standalone ones, might increase diagnostic yield, these genes are also less well studied, indicating uncertainty over their role in CASA pathogenesis. Rigorous prospective diagnostic yield studies of NGS-MGPs will aid in making decisions of panel selection for the diagnosis of CASAs.
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Affiliation(s)
- Maria Fernanda Villalba
- From the Bascom Palmer Eye Institute (M.F.V., T.C.P.C.), University of Miami Miller School of Medicine, Miami, Florida, USA; John P. Hussmann Institute for Human Genomics (M.F.V., G.B.), University of Miami Miller School of Medicine, Miami, Florida, USA; University of Miami Miller School of Medicine (M.F.V., C.M.L., P.P.), Miami, Florida, USA
| | - Chris Michael Li
- University of Miami Miller School of Medicine (M.F.V., C.M.L., P.P.), Miami, Florida, USA
| | - Parastou Pakravan
- University of Miami Miller School of Medicine (M.F.V., C.M.L., P.P.), Miami, Florida, USA
| | - Guney Bademci
- John P. Hussmann Institute for Human Genomics (M.F.V., G.B.), University of Miami Miller School of Medicine, Miami, Florida, USA; Department of Human Genetics (G.B.), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ta Chen Peter Chang
- From the Bascom Palmer Eye Institute (M.F.V., T.C.P.C.), University of Miami Miller School of Medicine, Miami, Florida, USA.
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2
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Beck M. Clinical Manifestation in Females with X-linked Metabolic Disorders: Genetic and Pathophysiological Considerations. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2021. [DOI: 10.1590/2326-4594-jiems-2020-0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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3
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Happle R. The PORCN non-Goltz spectrum (PONGOS): A new group of genetic disorders. Am J Med Genet A 2020; 185:13-14. [PMID: 33219742 DOI: 10.1002/ajmg.a.61984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/24/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Rudolf Happle
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
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4
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Allen LB, Genaro-Mattos TC, Anderson A, Porter NA, Mirnics K, Korade Z. Amiodarone Alters Cholesterol Biosynthesis through Tissue-Dependent Inhibition of Emopamil Binding Protein and Dehydrocholesterol Reductase 24. ACS Chem Neurosci 2020; 11:1413-1423. [PMID: 32286791 DOI: 10.1021/acschemneuro.0c00042] [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] [Indexed: 12/16/2022] Open
Abstract
Amiodarone is prescribed for the treatment and prevention of irregular heartbeats. Although effective in clinical practice, the long-term use of amiodarone has many unwanted side effects, including cardiac, pulmonary, hepatic, and neurological toxicities. Our objective was to elucidate effects of amiodarone exposure on the cholesterol metabolism in cultured neuronal and non-neuronal cells and in individuals taking amiodarone. We observed that amiodarone increases distinct cholesterol precursors in different cell types in a dose-dependent manner. In liver and kidney cell lines, amiodarone causes increase in desmosterol levels, and in primary cortical neurons and astrocytes, amiodarone increases zymosterol, zymostenol, and 8-dehydrocholesterol (8-DHC). We conclude that amiodarone inhibits two enzymes in the pathway, emopamil binding protein (EBP) and dehydrocholesterol reductase 24 (DHCR24). Cortical neurons and astrocytes are more sensitive to amiodarone than liver and kidney cell lines. We confirmed the inhibition of EBP enzyme by analyzing the sterol intermediates in EBP-deficient Neuro2a cells versus amiodarone-treated control Neuro2a cells. To determine if the cell culture experiments have clinical relevance, we analyzed serum samples from amiodarone users. We found that in patient serum samples containing detectable amount of amiodarone there are elevated levels of the sterol precursors zymosterol, 8-DHC, and desmosterol. This study illustrates the need for close monitoring of blood biochemistry during prolonged amiodarone use to minimize the risk of side effects.
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Affiliation(s)
- Luke B. Allen
- Department of Pediatrics, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Thiago C. Genaro-Mattos
- Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska 68105, United States
| | - Allison Anderson
- Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska 68105, United States
| | - Ned A. Porter
- Department of Chemistry, Vanderbilt Institute of Chemical Biology and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Károly Mirnics
- Munroe-Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska 68105, United States
| | - Zeljka Korade
- Department of Pediatrics, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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5
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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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6
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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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7
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Soler‐Cardona A, Brandau O, Laccone F, Tanew A, Radakovic S. De novo mutation of emopamil binding protein ( EBP) gene in a girl with Conradi-Hünermann-Happle syndrome. Clin Case Rep 2019; 7:1522-1525. [PMID: 31428380 PMCID: PMC6692985 DOI: 10.1002/ccr3.2213] [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: 01/31/2019] [Revised: 04/07/2019] [Accepted: 04/08/2019] [Indexed: 11/30/2022] Open
Abstract
Conradi-Hünermann-Happle syndrome is a rare X-linked dominant syndrome affecting the skin, skeletal system, and eyes. Here, we report on a female patient with a de novo heterozygous missense mutation c.301C>T (p.Trp101Arg) of the EMP (emopamil binding protein) gene.
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Affiliation(s)
| | - Oliver Brandau
- Institute of Medical GeneticsMedical University of ViennaViennaAustria
- Center for Human Genetics MannheimMannheimGermany
| | - Franco Laccone
- Institute of Medical GeneticsMedical University of ViennaViennaAustria
| | - Adrian Tanew
- Department of DermatologyMedical University of ViennaViennaAustria
- Private Dermatological PracticeViennaAustria
| | - Sonja Radakovic
- Department of DermatologyMedical University of ViennaViennaAustria
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8
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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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9
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Liu Y, Wang L, Xu B, Yang Y, Shan D, Wu Q. X-linked dominant chondrodysplasia punctata with severe phenotype in a female fetus: A case report. Medicine (Baltimore) 2019; 98:e13850. [PMID: 30608402 PMCID: PMC6344186 DOI: 10.1097/md.0000000000013850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
RATIONALE X-linked dominant chondrodysplasia punctata type 2 (CDPX2) is a condition involving facial, skin, and skeletal dysplasia as a result of a mutation in emopamil binding protein (EBP). It usually presents with mild symptoms in female patients but is fatal in male patients. PATIENT CONCERNS A fetus was diagnosed with asymmetrical short limbs and a narrow and small thorax by prenatal ultrasound examination at 24+5 weeks gestation. The pregnancy was terminated at 27 weeks of gestation; gross examination, postnatal X-ray and, whole exome analysis were performed to clarify the diagnosis. DIAGNOSIS A provisional diagnosis of fatal skeletal dysplasia was given and the definite diagnosis of CDPX2 was based on postnatal X-ray and genetic testing of the aborted fetus. INTERVENTION The pregnancy was terminated at 27 weeks' gestation after a fetal ultrasound indicated a severe abnormal phenotype. OUTCOMES Whole exome analysis of aborted tissue confirmed EBP mutation in this case. Unlike most case reports, this female patient presented a severe phenotype that was considered to be related to X-chromosome inactivation. LESSONS Chondrodysplasia punctata (CDP) should be considered if prenatal ultrasound shows high punctuate echoes at the metaphysis of long bones and asymmetrical short lower limbs. Postnatal X-ray and measurement of sterol levels in the amniotic fluid may aid in the diagnosis of CDP, but the condition can be confirmed with genetic testing of a blood sample or aborted tissue after delivery.
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Affiliation(s)
| | | | - Bin Xu
- Department of Radiology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China
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10
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Honigman A, De Cruz R, Sinclair R, Winship I. Chondrodysplasia punctata (
CDPX
2) in a male caused by single‐gene mosaicism: A 20‐year follow‐up. Australas J Dermatol 2018; 60:e160-e162. [DOI: 10.1111/ajd.12938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anthony Honigman
- Faculty of Medicine Nursing & Health Sciences Monash University Melbourne Victoria Australia
| | - Ryan De Cruz
- Department of Dermatology Royal Melbourne Hospital Melbourne Victoria Australia
| | - Rodney Sinclair
- Department of Medicine University of Melbourne Melbourne Victoria Australia
- Department of Dermatology Epworth HealthcareMelbourne Victoria Australia
| | - Ingrid Winship
- Department of Genetic Medicine Royal Melbourne Hospital Melbourne Victoria Australia
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11
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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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Abstract
Genetic mosaicism arises when a zygote harbors two or more distinct genotypes, typically due to de novo, somatic mutation during embryogenesis. The clinical manifestations largely depend on the differentiation status of the mutated cell; earlier mutations target pluripotent cells and generate more widespread disease affecting multiple organ systems. If gonadal tissue is spared-as in somatic genomic mosaicism-the mutation and its effects are limited to the proband, whereas mosaicism also affecting the gametes, such as germline or gonosomal mosaicism, is transmissible. Mosaicism is easily appreciated in cutaneous disorders, as phenotypically distinct mutant cells often give rise to lesions in patterns determined by the affected cell type. Genetic investigation of cutaneous mosaic disorders has identified pathways central to disease pathogenesis, revealing novel therapeutic targets. In this review, we discuss examples of cutaneous mosaicism, approaches to gene discovery in these disorders, and insights into molecular pathobiology that have potential for clinical translation.
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Affiliation(s)
- Young H Lim
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA; .,Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Zoe Moscato
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA;
| | - Keith A Choate
- Department of Dermatology, Yale University School of Medicine, New Haven, Connecticut 06520, USA; .,Departments of Pathology and Genetics, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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14
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Corso G, Dello Russo A, Gelzo M. Liver and the defects of cholesterol and bile acids biosynthesis: Rare disorders many diagnostic pitfalls. World J Gastroenterol 2017; 23:5257-5265. [PMID: 28839426 PMCID: PMC5550775 DOI: 10.3748/wjg.v23.i29.5257] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 05/01/2017] [Accepted: 07/04/2017] [Indexed: 02/06/2023] Open
Abstract
In recent decades, biotechnology produced a growth of knowledge on the causes and mechanisms of metabolic diseases that have formed the basis for their study, diagnosis and treatment. Unfortunately, it is well known that the clinical features of metabolic diseases can manifest themselves with very different characteristics and escape early detection. Also, it is well known that the prognosis of many metabolic diseases is excellent if diagnosed and treated early. In this editorial we briefly summarized two groups of inherited metabolic diseases, the defects of cholesterol biosynthesis and those of bile acids. Both groups show variable clinical manifestations but some clinical signs and symptoms are common in both the defects of cholesterol and bile acids. The differential diagnosis can be made analyzing sterol profiles in blood and/or bile acids in blood and urine by chromatographic techniques (GC-MS and LC-MS/MS). Several defects of both biosynthetic pathways are treatable so early diagnosis is crucial. Unfortunately their diagnosis is made too late, due either to the clinical heterogeneity of the syndromes (severe, mild and very mild) that to the scarcity of scientific dissemination of these rare diseases. Therefore, the delay in diagnosis leads the patient to the medical observation when the disease has produced irreversible damages to the body. Here, we highlighted simple clinical and laboratory descriptions that can potentially make you to suspect a defect in cholesterol biosynthesis and/or bile acids, as well, we suggest appropriate request of the laboratory tests that along with common clinical features can help to diagnose these defects.
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15
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Saral S, Vural A, Wollenberg A, Ruzicka T. A practical approach to ichthyoses with systemic manifestations. Clin Genet 2016; 91:799-812. [DOI: 10.1111/cge.12828] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/06/2016] [Accepted: 06/22/2016] [Indexed: 12/20/2022]
Affiliation(s)
- S. Saral
- Department of Dermatology and Venereology; Ankara University; Ankara Turkey
- Department of Dermatology and Allergology; Ludwig-Maximilian University; Munich Germany
| | - A. Vural
- Department of Neurology; Hacettepe University; Ankara Turkey
| | - A. Wollenberg
- Department of Dermatology and Allergology; Ludwig-Maximilian University; Munich Germany
| | - T. Ruzicka
- Department of Dermatology and Allergology; Ludwig-Maximilian University; Munich Germany
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16
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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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Hunter JM, Kiefer J, Balak CD, Jooma S, Ahearn ME, Hall JG, Baumbach-Reardon L. Review of X-linked syndromes with arthrogryposis or early contractures-aid to diagnosis and pathway identification. Am J Med Genet A 2015; 167A:931-73. [DOI: 10.1002/ajmg.a.36934] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 12/05/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Jesse M. Hunter
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Jeff Kiefer
- Knowledge Mining; Translational Genomics Research Institute; Phoenix Arizona
| | - Christopher D. Balak
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Sonya Jooma
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Mary Ellen Ahearn
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Judith G. Hall
- Departments of Medical Genetics and Pediatrics; University of British Columbia and BC Children's Hospital Vancouver; British Columbia Canada
| | - Lisa Baumbach-Reardon
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
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18
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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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19
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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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20
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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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21
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Kiritsi D, Schauer F, Wölfle U, Valari M, Bruckner-Tuderman L, Has C, Happle R. Targeting epidermal lipids for treatment of Mendelian disorders of cornification. Orphanet J Rare Dis 2014; 9:33. [PMID: 24607067 PMCID: PMC3975448 DOI: 10.1186/1750-1172-9-33] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 03/03/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Inherited ichthyoses or Mendelian disorders of cornification (MeDOC) are clinically heterogeneous disorders with high unmet therapeutic needs, which are characterized by skin hyperkeratosis and scaling. Some MeDOC types are associated with defects of the epidermal lipid metabolism, resulting in perturbed barrier permeability and subsequent epidermal hyperplasia, hyperkeratosis and inflammation. An example is the CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, an X-linked dominant multisystem MeDOC caused by mutations in the NSDHL (NAD(P)H steroid dehydrogenase-like protein) gene, which is involved in the distal cholesterol biosynthetic pathway. The skin manifestations of the CHILD syndrome have been attributed to two major mechanisms: deficiency of cholesterol, probably influencing the proper corneocyte membrane formation, and toxic accumulation of aberrant steroid precursors. METHODS Here we addressed the efficacy of an ointment containing cholesterol and simvastatin, an agent inhibiting endogenous cholesterol synthesis in a compassionate-use treatment of three patients with CHILD syndrome. To test the specificity of this therapeutic approach, we applied the same topical treatment to two patients with other types of MeDOC with disturbed skin lipid metabolism. RESULTS The therapy with simvastatin and cholesterol was highly effective and well-tolerated by the CHILD syndrome patients; only lesions in the body folds represented a therapeutic challenge. No improvement was noted in the patients with other types of MeDOC. CONCLUSIONS This therapy is inexpensive and accessible to every patient with CHILD syndrome, because both simvastatin and cholesterol are available worldwide. Our data provide initial evidence of the specificity of the therapeutic effect of the simvastatin-cholesterol ointment in CHILD syndrome in comparison to other types of MeDOC.
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Affiliation(s)
| | | | | | | | | | - Cristina Has
- Department of Dermatology, Medical Center-University of Freiburg, 79104 Freiburg, Germany.
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22
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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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23
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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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24
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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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25
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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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26
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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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