Browsing by Author "Al-Muhsen, Saleh"

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Accounting for genetic heterogeneity in homozygosity mapping: Application to Mendelian susceptibility to mycobacterial disease
(Bmj Publishing Group, 2011-08) Grant, Audrey V.; Dupuis, Stephanie Boisson; Herquelot, Eleonore; de Beaucoudrey, Ludovic; Santos, Orchidee Filipe; Nolan, Daniel K.; Feinberg, Jacqueline; Boland, Anne; Al-Muhsen, Saleh; Sanal, Özden; Çamcıoğlu, Yıldız; Palanduz, Ayşe; Bustamante, Jacinta; Casanova, Jean-Laurent; Abel, Laurent; Kılıç, Sara Şebnem; Uludağ Üniversitesi/Tıp Fakültesi/Pediatri Anabilim Dalı.; 0000-0001-8571-2581; AAH-1658-2021; 34975059200
Introduction Genome-wide homozygosity mapping is a powerful method for locating rare recessive Mendelian mutations. However, statistical power decreases dramatically in the presence of genetic heterogeneity. Methods The authors applied an empirical approach to test for linkage accounting for genetic heterogeneity by calculating the sum of positive per-family multipoint LOD scores (S) across all positions, and obtaining corresponding empirical p values (EmpP) through permutations. Results The statistical power of the approach was found to be consistently higher than the classical heterogeneity LOD by simulations. Among 21 first-cousin matings with a single affected child, for five families linked to a locus of interest and 16 families to other loci, S/EmpP achieved a power of 40% versus 28% for heterogeneity LOD at an alpha level of 0.001. The mean size of peak linkage regions was markedly higher for true loci than false positive regions. The S/EmpP approach was applied to a sample of 17 consanguineous families with Mendelian susceptibility to mycobacterial disease, leading to the identification of two mutations in IL12RB1 and TYK2 from the largest of six linkage regions at p<10(-3). Conclusions The S/EmpP approach is a flexible and powerful approach that can be applied to linkage analysis of families with suspected Mendelian disorders.
Human TYK2 deficiency: Mycobacterial and viral infections without hyper-ige syndrome
(Rockefeller Univ Press, 2015-09-21) Kreins, Alexandra Y.; Ciancanelli, Michael J.; Okada, Satoshi; Kong, Xiao-Fei; Ramirez-Alejo, Noe; Kılıç, Sara Şebnem; El Baghdadi, Jamila; Nonoyama, Shigeaki; Mahdaviani, Seyed Alireza; Ailal, Fatima; Bousfiha, Aziz; Mansouri, Davood; Nievas, Elma; Ma, Cindy S.; Rao, Geetha; Bernasconi, Andrea; Kuehn, Hye Sun; Niemela, Julie; Stoddard, Jennifer; Deveau, Paul; Cobat, Aurelie; El Azbaoui, Safa; Sabri, Ayoub; Lim, Che Kang; Sundin, Mikael; Avery, Danielle T.; Halwani, Rabih; Grant, Audrey V.; Boisson, Bertrand; Bogunovic, Dusan; Itan, Yuval; Moncada-Velez, Marcela; Martinez-Barricarte, Ruben; Migaud, Melanie; Deswarte, Caroline; Alsina, Laia; Kotlarz, Daniel; Klein, Christoph; Muller-Fleckenstein, Ingrid; Fleckenstein, Bernhard; Cormier-Daire, Valerie; Rose-John, Stefan; Picard, Capucine; Hammarstrom, Lennart; Puel, Anne; Al-Muhsen, Saleh; Abel, Laurent; Chaussabel, Damien; Rosenzweig, Sergio D.; Minegishi, Yoshiyuki; Tangye, Stuart G.; Bustamante, Jacinta; Casanova, Jean-Laurent; Boisson-Dupuis, Stephanie; KILIÇ GÜLTEKİN, SARA ŞEBNEM; Uludağ Üniversitesi/Tıp Fakültesi/Pediatrik İmmünoloji Anabilim Dalı; AAH-1658-2021
Autosomal recessive, complete TYK2 deficiency was previously described in a patient (P1) with intracellular bacterial and viral infections and features of hyper-IgE syndrome (HIES), including atopic dermatitis, high serum IgE levels, and staphylococcal abscesses. We identified seven other TYK2-deficient patients from five families and four different ethnic groups. These patients were homozygous for one of five null mutations, different from that seen in P1. They displayed mycobacterial and/or viral infections, but no HIES. All eight TYK2-deficient patients displayed impaired but not abolished cellular responses to (a) IL-12 and IFN-alpha/beta, accounting for mycobacterial and viral infections, respectively; (b) IL-23, with normal proportions of circulating IL-17(+) T cells, accounting for their apparent lack of mucocutaneous candidiasis; and (c) IL-10, with no overt clinical consequences, including a lack of inflammatory bowel disease. Cellular responses to IL-21, IL-27, IFN-gamma, IL-28/29 (IFN-lambda), and leukemia inhibitory factor (LIF) were normal. The leukocytes and fibroblasts of all seven newly identified TYK2-deficient patients, unlike those of P1, responded normally to IL-6, possibly accounting for the lack of HIES in these patients. The expression of exogenous wild-type TYK2 or the silencing of endogenous TYK2 did not rescue IL-6 hyporesponsiveness, suggesting that this phenotype was not a consequence of the TYK2 genotype. The core clinical phenotype of TYK2 deficiency is mycobacterial and/or viral infections, caused by impaired responses to IL-12 and IFN-alpha/beta. Moreover, impaired IL-6 responses and HIES do not appear to be intrinsic features of TYK2 deficiency in humans.