Novel CARMIL2 Mutations in Patients with Variable Clinical Dermatitis, Infections, and Combined Immunodeficiency

Bibliographic Details
Title: Novel CARMIL2 Mutations in Patients with Variable Clinical Dermatitis, Infections, and Combined Immunodeficiency
Authors: Anas M. Alazami, Maryam Al-Helale, Safa Alhissi, Bandar Al-Saud, Huda Alajlan, Dorota Monies, Zeeshan Shah, Mohamed Abouelhoda, Rand Arnaout, Hasan Al-Dhekri, Nouf S. Al-Numair, Hazem Ghebeh, Farrukh Sheikh, Hamoud Al-Mousa
Source: Frontiers in Immunology, Vol 9 (2018)
Publisher Information: Frontiers Media S.A., 2018.
Publication Year: 2018
Collection: LCC:Immunologic diseases. Allergy
Subject Terms: CARMIL2, immunodeficiency, whole exome sequencing, autosomal recessive, RLTPR, dermatitis, Immunologic diseases. Allergy, RC581-607
More Details: Combined immunodeficiencies are a heterogeneous collection of primary immune disorders that exhibit defects in T cell development or function, along with impaired B cell activity even in light of normal B cell maturation. CARMIL2 (RLTPR) is a protein involved in cytoskeletal organization and cell migration, which also plays a role in CD28 co-signaling of T cells. Mutations in this protein have recently been reported to cause a novel primary immunodeficiency disorder with variable phenotypic presentations. Here, we describe seven patients from three unrelated, consanguineous multiplex families that presented with dermatitis, esophagitis, and recurrent skin and chest infections with evidence of combined immunodeficiency. Through the use of whole exome sequencing and autozygome-guided analysis, we uncovered two mutations not previously reported (p.R50T and p.L846Sfs) in CARMIL2. Real-time PCR analysis revealed that the biallelic frameshift mutation is under negative selection, likely due to nonsense-mediated RNA decay and leading to loss of detectable protein upon immunoblotting. Protein loss was also observed for the missense mutation, and 3D modeling suggested a disturbance in structural stability due to an increase in the electrostatic energy for the affected amino acid and surrounding residues. Immunophenotyping revealed that patient Treg counts were significantly depressed, and that CD4+ T cells were heavily skewed towards the naïve status. CD3/CD28 signaling impairment was evidenced by reduced proliferative response to stimulation. This work broadens the allelic heterogeneity associated with CARMIL2 and highlights a deleterious missense alteration located outside the leucine-rich repeat of the protein, where all other missense mutations have been reported to date.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1664-3224
Relation: http://journal.frontiersin.org/article/10.3389/fimmu.2018.00203/full; https://doaj.org/toc/1664-3224
DOI: 10.3389/fimmu.2018.00203
Access URL: https://doaj.org/article/e7cf1774ab76495abacdfa3118ef3f8a
Accession Number: edsdoj.7cf1774ab76495abacdfa3118ef3f8a
Database: Directory of Open Access Journals
More Details
ISSN:16643224
DOI:10.3389/fimmu.2018.00203
Published in:Frontiers in Immunology
Language:English