Medicine (Baltimore) 2014 Dec;93(29):e327
From the Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, Canada (IF, EH, FLD); Department of Microbiology and Immunology, CHU Sainte-Justine, Montreal, Canada (IF, FLD); CHU Sainte-Justine Research Center, Montreal, Canada (IF, NP, EH, HD, FLD); Department of Pathology and Cell Biology, CHU Sainte-Justine and University of Montreal, Montreal, Canada (NP); Department of Paediatrics, University of Montreal, Montreal, Canada (VM, EH, HD, FLD); Division of Gastroenterology, Hepatology and Nutrition, CHU Sainte-Justine, Montreal, Canada (VM); Histology Facility, IRIC, University of Montreal, Montreal, Montreal, Canada (MB); Medical Genetics Service, University of Sherbrooke, Sherbrooke, Canada (BM); and Division of Rheumatology, Immunology and Allergology, CHU Sainte-Justine Montreal, Canada (EH, HD, FLD).
Hereditary multiple intestinal atresia (HMIA) is a rare cause of intestinal obstruction in humans associated with a profound combined immune deficiency. Deleterious mutations of the tetratricopeptide repeat domain-7A (TTC7A) gene lead to HMIA, although the mechanism(s) causing the disease in TTC7A deficiency has (have) not yet been clearly identified. To evaluate the consequences of TTC7A deficiency, we studied the morphology of several organs from HMIA patients at different developmental stages, as well as the expression of the TTC7A protein. We performed histological and immunohistochemical analyses on biopsies and autopsies of 6 patients and 1 fetus with HMIA. Moreover, we characterized for the first time the expression of the TTC7A protein by immunostaining it in several organs from control (including fetal samples), infants, and 1 fetus with HMIA. Besides the gastrointestinal tract, HMIA disease was associated with morphological alterations in multiple organs: thymus, lung, spleen, and liver. Moreover, we demonstrated that normal TTC7A protein was expressed in the cytoplasm of epithelial cells of the intestine, thymus, and pancreas. Surprisingly, altered TTC7A protein was highly expressed in tissues from patients, mainly in the epithelial cells. We have established that HMIA associated with a TTC7A defect is characterized by multiorgan impairments. Overall, this report suggests that TTC7A protein is critical for the proper development, preservation, and/or function of thymic and gastrointestinal epithelium.