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Mutational analysis of the PHEX gene: novel point mutations and detection of large deletions by MLPA in patients with X-linked hypophosphatemic rickets.
Calcif Tissue Int. 2009 Sep; 85(3):211-20.CT

Abstract

X-Linked hypophosphatemic rickets (HYP, XLH) is a disorder of phosphate homeostasis, characterized by renal phosphate wasting and hypophosphatemia, with normal to low 1,25-dihydroxy vitamin D3 serum levels. The purpose of our study was the detection of inactivating mutations in the PHEX gene, the key enzyme in the pathogenesis of XLH. The 16 patients, representing eight families, presented with suspected XLH from biochemical and clinical evidence. All 16 were referred for mutational analysis of the PHEX gene. We detected three novel disease-causing mutations, C59S, Q394X, and W602, for which a loss of function can be predicted. A G28S variation, found in two healthy probands, may be a rare polymorphism. Another mutation, A363 V, is localized on the same allele as the C59S mutation, thus its functional consequences cannot be proven. Furthermore, we detected a deletion of three nucleotides in exon 15 which resulted in the loss of amino acid threonine 535. Heterozygosity of this mutation in a male patient without any chromosomal aberrations suggests its presence as a mosaic. Novel large deletions were detected using multiplex ligation-dependent probe amplification (MLPA) analysis. Two of these deletions, loss of exon 22 alone or exons 21 and 22 together, may result in the translation of a C-terminal truncated protein. Two large deletions comprise exons 1-9 and exons 4-20, respectively, and presumably result in a nonfunctional protein. We conclude that molecular genetic analysis confirms the clinical diagnosis of XLH and should include sequence analysis as well as the search for large deletions, which is facilitated by MLPA.

Authors+Show Affiliations

Endocrine Practice Prof. Raue, Heidelberg, Germany. Susanne.Clausmeyer@raue-endokrinologie.deNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19513579

Citation

Clausmeyer, S, et al. "Mutational Analysis of the PHEX Gene: Novel Point Mutations and Detection of Large Deletions By MLPA in Patients With X-linked Hypophosphatemic Rickets." Calcified Tissue International, vol. 85, no. 3, 2009, pp. 211-20.
Clausmeyer S, Hesse V, Clemens PC, et al. Mutational analysis of the PHEX gene: novel point mutations and detection of large deletions by MLPA in patients with X-linked hypophosphatemic rickets. Calcif Tissue Int. 2009;85(3):211-20.
Clausmeyer, S., Hesse, V., Clemens, P. C., Engelbach, M., Kreuzer, M., Becker-Rose, P., Spital, H., Schulze, E., & Raue, F. (2009). Mutational analysis of the PHEX gene: novel point mutations and detection of large deletions by MLPA in patients with X-linked hypophosphatemic rickets. Calcified Tissue International, 85(3), 211-20. https://doi.org/10.1007/s00223-009-9260-8
Clausmeyer S, et al. Mutational Analysis of the PHEX Gene: Novel Point Mutations and Detection of Large Deletions By MLPA in Patients With X-linked Hypophosphatemic Rickets. Calcif Tissue Int. 2009;85(3):211-20. PubMed PMID: 19513579.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mutational analysis of the PHEX gene: novel point mutations and detection of large deletions by MLPA in patients with X-linked hypophosphatemic rickets. AU - Clausmeyer,S, AU - Hesse,V, AU - Clemens,P C, AU - Engelbach,M, AU - Kreuzer,M, AU - Becker-Rose,P, AU - Spital,H, AU - Schulze,E, AU - Raue,F, Y1 - 2009/06/10/ PY - 2008/10/27/received PY - 2009/04/30/accepted PY - 2009/6/11/entrez PY - 2009/6/11/pubmed PY - 2009/11/17/medline SP - 211 EP - 20 JF - Calcified tissue international JO - Calcif Tissue Int VL - 85 IS - 3 N2 - X-Linked hypophosphatemic rickets (HYP, XLH) is a disorder of phosphate homeostasis, characterized by renal phosphate wasting and hypophosphatemia, with normal to low 1,25-dihydroxy vitamin D3 serum levels. The purpose of our study was the detection of inactivating mutations in the PHEX gene, the key enzyme in the pathogenesis of XLH. The 16 patients, representing eight families, presented with suspected XLH from biochemical and clinical evidence. All 16 were referred for mutational analysis of the PHEX gene. We detected three novel disease-causing mutations, C59S, Q394X, and W602, for which a loss of function can be predicted. A G28S variation, found in two healthy probands, may be a rare polymorphism. Another mutation, A363 V, is localized on the same allele as the C59S mutation, thus its functional consequences cannot be proven. Furthermore, we detected a deletion of three nucleotides in exon 15 which resulted in the loss of amino acid threonine 535. Heterozygosity of this mutation in a male patient without any chromosomal aberrations suggests its presence as a mosaic. Novel large deletions were detected using multiplex ligation-dependent probe amplification (MLPA) analysis. Two of these deletions, loss of exon 22 alone or exons 21 and 22 together, may result in the translation of a C-terminal truncated protein. Two large deletions comprise exons 1-9 and exons 4-20, respectively, and presumably result in a nonfunctional protein. We conclude that molecular genetic analysis confirms the clinical diagnosis of XLH and should include sequence analysis as well as the search for large deletions, which is facilitated by MLPA. SN - 1432-0827 UR - https://www.unboundmedicine.com/medline/citation/19513579/Mutational_analysis_of_the_PHEX_gene:_novel_point_mutations_and_detection_of_large_deletions_by_MLPA_in_patients_with_X_linked_hypophosphatemic_rickets_ L2 - https://dx.doi.org/10.1007/s00223-009-9260-8 DB - PRIME DP - Unbound Medicine ER -