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Wang D, Qin J, Zhao C, He X. Homozygosity for a DTDST mutation in a child with multiple epiphyseal dysplasia. J Pediatr Endocrinol Metab 2014; 27:75-80. [PMID: 23934641 DOI: 10.1515/jpem-2013-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 07/15/2013] [Indexed: 11/15/2022]
Abstract
BACKGROUND Multiple epiphyseal dysplasia (MED) is one of the common hereditary osteochondrodysplasias. Mutations in diastrophic dysplasia sulfate transporter gene (DTDST) result in recessive MED. OBJECTIVE To investigate the possible gene mutation in a recessive MED patient. SUBJECTS A boy with typical clinical features of recessive MED and his parents. METHODS Clinical and radiological evaluations, DTDST gene sequence analysis, and sulfate uptake assay were performed on the patient and his parents. RESULTS The patient showed typical symptoms of recessive MED. The radiological evaluation confirmed dysplasia in multiple epiphysis of the patient, while his parents did not show the similar clinical and radiological features. Gene sequence showed the patient was homozygous of A2092T (T689S) mutation, while his parents were both of heterozygous of the same mutation. No such mutation in DTDST gene was found in 81 normal control individuals. The patient showed reduced sulfate uptake ability in dermal fibroblast compared with his parents and normal controls. CONCLUSION The homozygous A2092T (T689S) mutation could be one of the mutations in the DTDST gene causing MED.
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Dwyer E, Hyland J, Modaff P, Pauli RM. Genotype-phenotype correlation in DTDST dysplasias: Atelosteogenesis type II and diastrophic dysplasia variant in one family. Am J Med Genet A 2011; 152A:3043-50. [PMID: 21077202 DOI: 10.1002/ajmg.a.33736] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in diastrophic dysplasia sulfate transporter (DTDST) cause a spectrum of autosomal recessive chondrodysplasias. In decreasing order of severity, they include processes designated as achondrogenesis type IB (ACG-1B), atelosteogenesis type II (AO2), diastrophic dysplasia (DTD), diastrophic dysplasia variant (DTDv), and recessively inherited multiple epiphyseal dysplasia (rMED). This is the first report of an extended family with unequivocally distinct phenotypes on the DTDST spectrum. Two siblings have DTDv and their first cousin had AO2. They all share the common Finnish mutation (IVS1 + 2C>T). The two patients with DTDv have the previously reported R279W extracellular domain missense mutation. The second mutation in the patient with AO2 is c.172delA, a deletion of one nucleotide causing a previously unreported frameshift mutation. This is the first published case of an individual with a frameshift mutation combined with the Finnish mutation. These three patients provide an opportunity, in concert with a review of previous literature, to further examine the genotype-phenotype correlation of DTDST. Analysis suggests that, while the DTDST family of disorders contains at least seven different conditions, mutations in the DTDST gene, in fact, appear to cause a phenotypic continuum. Furthermore, DTDST genotype alone is an imperfect predictor of clinical severity along this continuum.
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Affiliation(s)
- Ellen Dwyer
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Chang MH, Plata C, Sindic A, Ranatunga WK, Chen AP, Zandi-Nejad K, Chan KW, Thompson J, Mount DB, Romero MF. Slc26a9 is inhibited by the R-region of the cystic fibrosis transmembrane conductance regulator via the STAS domain. J Biol Chem 2009; 284:28306-28318. [PMID: 19643730 DOI: 10.1074/jbc.m109.001669] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SLC26 proteins function as anion exchangers, channels, and sensors. Previous cellular studies have shown that Slc26a3 and Slc26a6 interact with the R-region of the cystic fibrosis transmembrane conductance regulator (CFTR), (R)CFTR, via the Slc26-STAS (sulfate transporter anti-sigma) domain, resulting in mutual transport activation. We recently showed that Slc26a9 has both nCl(-)-HCO(3)(-) exchanger and Cl(-) channel function. In this study, we show that the purified STAS domain of Slc26a9 (a9STAS) binds purified (R)CFTR. When Slc26a9 and (R)CFTR fragments are co-expressed in Xenopus oocytes, both Slc26a9-mediated nCl(-)-HCO(3)(-) exchange and Cl(-) currents are almost fully inhibited. Deletion of the Slc26a9 STAS domain (a9-DeltaSTAS) virtually eliminated the Cl(-) currents with only a modest affect on nCl(-)-HCO(3)(-) exchange activity. Co-expression of a9-DeltaSTAS and the (R)CFTR fragment did not alter the residual a9-DeltaSTAS function. Replacing the Slc26a9 STAS domain with the Slc26a6 STAS domain (a6-a9-a6) does not change Slc26a9 function and is no longer inhibited by (R)CFTR. These data indicate that the Slc26a9-STAS domain, like other Slc26-STAS domains, binds CFTR in the R-region. However, unlike previously reported data, this binding interaction inhibits Slc26a9 ion transport activity. These results imply that Slc26-STAS domains may all interact with (R)CFTR but that the physiological outcome is specific to differing Slc26 proteins, allowing for dynamic and acute fine tuning of ion transport for various epithelia.
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Affiliation(s)
- Min-Hwang Chang
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Consuelo Plata
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106; Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City 14000, Mexico
| | - Aleksandra Sindic
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Wasantha K Ranatunga
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - An-Ping Chen
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Kambiz Zandi-Nejad
- Renal Division, Brigham and Women's Hospital, Boston, Massachusetts 02115
| | - Kim W Chan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106
| | - James Thompson
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - David B Mount
- Renal Division, Brigham and Women's Hospital, Boston, Massachusetts 02115; Renal Division, Veterans Affairs Boston Healthcare System, West Roxbury, Massachusetts 02132
| | - Michael F Romero
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106; Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905.
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Vogt G, Vogt B, Chuzhanova N, Julenius K, Cooper DN, Casanova JL. Gain-of-glycosylation mutations. Curr Opin Genet Dev 2007; 17:245-51. [PMID: 17467977 DOI: 10.1016/j.gde.2007.04.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Accepted: 04/16/2007] [Indexed: 10/23/2022]
Abstract
Disease-causing missense (and other in-frame) mutations can exert their deleterious effects at the cellular level through multiple mechanisms. A pathogenic mechanism involves the addition of a novel N-linked glycan. Up to 1.4% of known disease-causing missense mutations are predicted to give rise to gains-of-glycosylation. For some of these mutations, the novel glycans have been shown to be both necessary and sufficient to account for the deleterious impact of the mutation. The chemical complementation of cells from patients in vitro with various modifiers of glycosylation has been demonstrated and raises the possibility of specific chemical treatments for patients bearing gain-of-glycosylation mutations.
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Affiliation(s)
- Guillaume Vogt
- Laboratory of Human Genetics of Infectious Diseases, INSERM, U550, Paris 75015, France.
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Kocakoc E, Kiris A. Achondrogenesis type II with normally developed extremities: a case report. Prenat Diagn 2002; 22:594-7. [PMID: 12124695 DOI: 10.1002/pd.340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present a case of achondrogenesis type II with normally developed extremities that was confirmed with postmortem ultrasonographic and radiographic examination. The length of the long bones may vary and the diagnosis of achondrogenesis should not be ruled out with normally developed extremities. Intrauterine sonographic examination of the vertebrae is very important and the absence of vertebral body ossification may be the unique finding of achondrogenesis type II. Axial ultrasonographic images and postmortem plain radiographs are useful to clarify the pathology.
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Affiliation(s)
- Ercan Kocakoc
- Department of Radiology, Firat University, Faculty of Medicine, Elazig, Turkey.
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Rossi A, Superti-Furga A. Mutations in the diastrophic dysplasia sulfate transporter (DTDST) gene (SLC26A2): 22 novel mutations, mutation review, associated skeletal phenotypes, and diagnostic relevance. Hum Mutat 2001; 17:159-71. [PMID: 11241838 DOI: 10.1002/humu.1] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mutations in the DTDST gene can result in a family of skeletal dysplasia conditions which comprise two lethal disorders, achondrogenesis type 1B (ACG1B) and atelosteogenesis type 2 (AO2); and two non-lethal disorders, diastrophic dysplasia (DTD) and recessive multiple epiphyseal dysplasia (rMED). The gene product is a sulfate-chloride exchanger of the cell membrane. Inactivation of the sulfate exchanger leads to intracellular sulfate depletion and to the synthesis of undersulfated proteoglycans in susceptible cells such as chondrocytes and fibroblasts. Genotype-phenotype correlations are recognizable, with mutations predicting a truncated protein or a non-conservative amino acid substitution in a transmembrane domain giving the severe phenotypes, and non-transmembrane amino acid substitutions and splice site mutations giving the milder phenotypes. The clinical phenotype is modulated strictly by the degree of residual activity. Over 30 mutations have been observed, including 22 novel mutations reported here. The most frequent mutation, 862C>T (R279W), is a mild mutation giving the rMED phenotype when homozygous and mostly DTD when compounded; occurrence at a CpG dinucleotide and its panethnic distribution suggest independent recurrence. Mutation IVS1+2T>C is the second most common mutation, but is very frequent in Finland. It produces low levels of correctly spliced mRNA, and results in DTD when homozygous. Two other mutations, 1045-1047delGTT (V340del) and 558C>T (R178X), are associated with severe phenotypes and have been observed in multiple patients. Most other mutations are rare. Heterozygotes are clinically unaffected. When clinical samples are screened for radiologic and histologic features compatible with the ACG1B/AO2/DTD/rMED spectrum prior to analysis, the mutation detection rate is high (over 90% of alleles), and appropriate genetic counseling can be given. The sulfate uptake or sulfate incorporation assays in cultured fibroblasts have largely been replaced by mutation analysis, but may still be useful in cases where mutation analysis is not informative. Although supplementation of patients' cultured cells with thiols may bypass the transporter defect and enhance sulfation of proteoglycans, therapeutic approaches are not yet available. Mouse models for this and other disorders of sulfate metabolism are being developed to help in developing therapeutic treatments.
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Affiliation(s)
- A Rossi
- Division of Metabolic and Molecular Pediatrics, University Children's Hospital, Zurich, Switzerland
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