1
|
Bougacha-Elleuch N, Charfi N, Miled N, Bouhajja H, Belguith N, Mnif M, Jaurge P, Chikhrouhou N, Ayadi H, Hachicha M, Abid M. Segregation of S292F TPO gene mutation in three large Tunisian families with thyroid dyshormonogenesis: evidence of a founder effect. Eur J Pediatr 2015; 174:1491-501. [PMID: 25968604 DOI: 10.1007/s00431-015-2550-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED We aimed to identify causal mutation(s) in 13 patients with thyroid dyshormonogenesis (TD) from three consanguineous Tunisian families. A 12-year clinical follow-up showed phenotypic variability ranging from the presence to the absence of goiter, sensorineural deafness, and mental retardation. Genetic analysis using microsatellite markers within two candidate genes (TPO and PDS) gave evidence of linkage with the TPO gene. Sequencing of its 17 exons and their flanking intron-exon junctions revealed the previously described c.875C>T (p.S292F) mutation in homozygous state. No additional mutations were found in either a 900 bp of the TPO gene promoter or PDS gene. In silico analysis showed that p.S292F mutation might reduce the catalytic cavity of the TPO which would restrict access of a potential substrate to the catalytic pocket. Using 4SNPs and one microsatellite marker in the TPO gene, an associated haplotype: G-C-G-G-214 was found, giving evidence of a founder mutation. CONCLUSION This is the first description of a TD causing mutation in Tunisia and thus may help to develop a genetic screening protocol for congenital hypothyroidism in the studied region. Although structural modeling suggested a pathogenic effect of this mutation, functional studies are needed. Additional causing and/or modifier genes, together with late diagnosis could explain the clinical variability observed in our patients.
Collapse
Affiliation(s)
- Noura Bougacha-Elleuch
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia.
| | - Nadia Charfi
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
| | - Nabil Miled
- Laboratoire de Biochimie et de Génie Enzymatique des Lipases, Ecole Nationale d'Ingénieurs de Sfax, Route Soukra BP W, Sfax, Tunisia
| | - Houda Bouhajja
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Neila Belguith
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine, Sfax, Tunisia
| | - Mouna Mnif
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
| | - Paula Jaurge
- Unidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP, Porto, Portugal
| | | | - Hammadi Ayadi
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia
| | | | - Mohamed Abid
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
| |
Collapse
|
2
|
Veblen KE, Nehring KC, McGlone CM, Ritchie ME. Contrasting effects of different mammalian herbivores on sagebrush plant communities. PLoS One 2015; 10:e0118016. [PMID: 25671428 PMCID: PMC4324772 DOI: 10.1371/journal.pone.0118016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 01/07/2015] [Indexed: 11/28/2022] Open
Abstract
Herbivory by both grazing and browsing ungulates shapes the structure and functioning of terrestrial ecosystems worldwide, and both types of herbivory have been implicated in major ecosystem state changes. Despite the ecological consequences of differences in diets and feeding habits among herbivores, studies that experimentally distinguish effects of grazing from spatially co-occurring, but temporally segregated browsing are extremely rare. Here we use a set of long-term exclosures in northern Utah, USA, to determine how domestic grazers vs. wild ungulate herbivores (including browsers and mixed feeders) affect sagebrush-dominated plant communities that historically covered ~62 million ha in North America. We sampled plant community properties and found that after 22 years grazing and browsing elicited perceptible changes in overall plant community composition and distinct responses by individual plant species. In the woody layer of the plant community, release from winter and spring wild ungulate herbivory increased densities of larger Wyoming big sagebrush (Artemisia tridentata, ssp. wyomingensis) at the expense of small sagebrush, while disturbance associated with either cattle or wild ungulate activity alone was sufficient to increase bare ground and reduce cover of biological soil crusts. The perennial bunchgrass, bottlebrush squirretail (Elymus elymoides), responded positively to release from summer cattle grazing, and in turn appeared to competitively suppress another more grazing tolerant perennial grass, Sandberg's blue grass (Poa secunda). Grazing by domestic cattle also was associated with increased non-native species biomass. Together, these results illustrate that ungulate herbivory has not caused sagebrush plant communities to undergo dramatic state shifts; however clear, herbivore-driven shifts are evident. In a dry, perennial-dominated system where plant community changes can occur very slowly, our results provide insights into potential long-term trajectories of these plant communities under different large herbivore regimes. Our results can be used to guide long-term management strategies for sagebrush systems and improve habitat for endemic wildlife species such as sage-grouse (Centrocercus spp.).
Collapse
Affiliation(s)
- Kari E. Veblen
- Ecology Center and Department of Wildland Resources, Utah State University, Logan, Utah, United States of America
| | - Kyle C. Nehring
- Ecology Center and Department of Wildland Resources, Utah State University, Logan, Utah, United States of America
| | - Christopher M. McGlone
- USDA-ARS Pollinating Insect Research Unit, Utah State University, Logan, Utah, United States of America
| | - Mark E. Ritchie
- Department of Biology, Syracuse University, Syracuse, New York, United States of America
| |
Collapse
|