Genetic predictors of celiac disease, lactose intolerance, and vitamin D function and presence of peptide morphins in urine of children with neurodevelopmental disorders

Katarina Bojovića†, Biljana Stankovićb†, Nikola Koturb, Dijana Krstić-Miloševićc http://orcid.org/0000-0001-6820-4809, Vladimir Gašićb, Sonja Pavlovićb, Branka Zukićb & Đurđica Ignjatovićc* http://orcid.org/0000-0003-3750-1303a Psychiatry Clinic “Dr Selaković”, Belgrade, Serbiab Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade, Belgrade, Serbiac Institute for Biological Research “Siniša Stanković”, University of Belgrade, Belgrade, SerbiaCorresponding author: Djurdjica Ignjatovic, Bulevar despota Stefana 142, 11060 Belgrade, Serbia. Email: djurdjica@ibiss.bg.ac.rs† Authors contributed equally to this work.Gastrointestinal disturbances, nutritional deficiencies, and food intolerances are frequently observed in children with neurodevelopmental disorders (NDD). To reveal possible association of celiac disease risk variants (HLA-DQ), lactose intolerance associated variant (LCT-13910C>T) as well as variant associated with vitamin D function (VDR FokI) with NDD, polymerase chain reaction-based methodology was used. Additionally, intestinal peptide permeability was estimated in NDD patients and healthy children by measuring the level of peptides in urine using high-performance liquid chromatography. Levels of opioid peptides, casomorphin 8, and gluten exorphin C were significantly elevated in urine samples of NDD patients (P = 0.004 and P = 0.005, respectively), but no association of genetic risk variants for celiac disease and lactose intolerance with NDD was found. Our results indicate that increased intestinal peptide permeability observed in analyzed NDD patients is not associated with genetic predictors of celiac disease or lactose intolerance. We have also found that FF genotype of VDR FokI and lower serum levels of vitamin D (25-OH) showed association with childhood autism (CHA), a subgroup of NDD. We hypothesize that vitamin D might be important for the development of CHA.