[Show abstract][Hide abstract] ABSTRACT: RECQ DNA helicases play critical roles in maintaining genomic stability, but their role in development has been less well studied. Rothmund-Thomson syndrome, RAPADILINO, and Baller-Gerold syndrome are rare genetic disorders caused by mutations in the RECQL4 gene. These patients have significant skeletal developmental abnormalities including radial ray, limb and craniofacial defects. To investigate the role of Recql4 in the developing skeletal system, we generated Recql4 conditional knockout mice targeting the skeletal lineage. Inactivation of Recql4 using the Prx1-Cre transgene led to limb abnormalities and craniosynostosis mimicking the major bone findings in human RECQL4 patients. These Prx1-Cre+;Recql4fl/fl mice as well as Col2a1-Cre+;Recql4fl/fl mice exhibited growth plate defects and an increased p53 response in affected tissues. Inactivation of Trp53 in these Recql4 mutants resulted in genetic rescue of the skeletal phenotypes, indicating an in vivo interaction between Recql4 and Trp53, and p53 activation as an underlying mechanism for the developmental bone abnormalities in RECQL4 disorders. Our findings show that RECQL4 is critical for skeletal development by modulating p53 activity in vivo. This article is protected by copyright. All rights reserved
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 06/2015; 30(6). DOI:10.1002/jbmr.2436 · 6.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Poikiloderma with Neutropenia (PN), Clericuzio-Type (OMIM #604173) is characterized by poikiloderma, chronic neutropenia, recurrent sinopulmonary infections, bronchiectasis, and nail dystrophy. First described by Clericuzio in 1991 in 14 patients of Navajo descent, it has since also been described in non-Navajo patients. C16orf57 has recently been identified as a causative gene in PN. The purpose of our study was to describe a spectrum of C16orf57 mutations in a cohort of PN patients including five patients of Athabaskan (Navajo and Apache) ancestry. Eleven patients from eight kindreds were enrolled in an IRB-approved study at Baylor College of Medicine. Five patients were of Athabaskan ancestry. PCR amplification and sequencing of the entire coding region of the C16orf57 gene was performed on genomic DNA. We identified biallelic C16orf57 mutations in all 11 PN patients in our cohort. The seven new deleterious mutations consisted of deletion (2), nonsense (3), and splice site (2) mutations. The patients of Athabaskan ancestry all had a common deletion mutation (c.496delA) which was not found in the six non-Athabaskan patients. Mutations in the C16orf57 gene have been identified thus far in all patients studied with a clinical diagnosis of PN. We have identified seven new mutations in C16orf57 in PN patients. One of these is present in all patients of Athabaskan descent, suggesting that c.496delA represents the PN-causative mutation in this subpopulation.
American Journal of Medical Genetics Part A 02/2011; 155A(2):337-42. DOI:10.1002/ajmg.a.33807 · 2.16 Impact Factor