Coeliac disease is an inflammatory disorder of the small intestine with an autoimmune component and strong heritability. Genetic studies have confirmed strong association to HLA and identified 39 nonHLA risk genes, mostly immune-related. Over 50% of the disease-associated single nucleotide polymorphisms are correlated with gene expression. Most of the coeliac disease-associated regions are shared with other immune-related diseases, as well as with metabolic, haematological or neurological traits, or cancer. We review recent progress in the genetics of coeliac disease and describe the pathways these genes are in, the functional consequences of the associated markers on gene expression and the genes shared between coeliac disease and other traits.

ABSTRACT: Celiac Disease (CD) occurs in patients with Type 1 Diabetes (T1D) ranging the prevalence of 4.4-11.1% versus 0.5% of the general population. The mechanism of association of these two diseases involves a shared genetic background: HLA genotype DR3-DQ2 and DR4-DQ8 are strongly associated with T1D, DR3-DQ2 with CD. The classical severe presentation of CD rarely occurs in T1D patients, but more often patients have few/mild symptoms of CD or are completely asymptomatic (silent CD). In fact diagnosis of CD is regularly performed by means of the screening in T1D patients. The effects of gluten-free diet (GFD) on the growth and T1D metabolic control in CD/T1D patient are controversial. Regarding of the GFD composition, there is a debate on the higher glycaemic index of gluten-free foods respect to gluten-containing foods; furthermore GFD could be poorer of fibers and richer of fat. The adherence to GFD by children with CD-T1D has been reported generally below 50%, lower respect to the 73% of CD patients, a lower compliance being more frequent among asymptomatic patients. The more severe problems of GFD adherence usually occur during adolescence when in GFD non compliant subjects the lowest quality of life is reported. A psychological and educational support should be provided for these patients.

Coeliac disease, epilepsy and cerebral calcifications (CEC) syndrome is a rare clinical condition. One hundred and seventy-one patients have been reported in the literature. Patients are mostly from Italy, Spain, and Argentina, suggesting a geographically restricted condition. Epilepsy is more frequently characterized by occipital seizures. It may be benign or drug-resistant, sometime evolving into severe epileptic encephalopathy. Gluten free diet (GFD) efficacy seems to be inversely related to the duration of epilepsy and the young age of the patient. Patients with cerebral calcifications (CC) and coeliac disease (CD) without epilepsy are considered as having an incomplete form of CEC syndrome. Some patients with epilepsy and CC without CD are supposed to have a CEC syndrome with silent or latent CD. Whether CEC syndrome is a genetic condition, or whether epilepsy and/or CC are a consequence of an untreated CD is unknown yet. Since histopathological findings seem to be the expression of vascular calcified malformation, CEC syndrome may be considered a genetically determined entity, such as a type of Sturge-Weber-like phacomatosis. Moreover, CEC, as well as CD, is associated with HLA-DQ2 and HLA-DQ8 phenotype and genotype. The progressive growth and late occurrence of CC before beginning a GFD, the demonstration of anti-gliadin antibodies in the cerebro-spinal fluid and the association with HLA class II genes, suggest that an immune reaction originating from the jejunal mucosa, triggered by gliadin in gluten intolerance predisposed subjects (HLA phenotype) may be responsible for seizures and CC. Moreover, a long-lasting untreated CD folic acid deficiency may cause calcifications. Probably, CEC is considered a genetic, non-inherited, ethnically and geographically restricted syndrome associated with environmental factors.