FADES: A longitudinal birth cohort study to understand why children with Down’s syndrome are at increased risk of autoimmunity

Background: Children with Down’s syndrome (DS) are at increased risk of islet, gut and thyroid autoimmunity. Onset of diabetes is accelerated in children with DS compared with the general population with 22% diagnosed before the age of 2 years. In addition, children with DS and diabetes have less HLA class II risk than expected. Understanding why children with DS are at increased risk of early-onset autoimmunity is the objective of FADES (Feeding and Autoimmunity in Down’s Syndrome Evaluation Study).

Methods: FADES is a longitudinal UK birth cohort to study the associations between early feeding, infections, antibiotic use, the gut microbiome and the appearance of autoimmunity in children with DS. Data and samples are collected through online questionnaires and home sampling kits respectively. Baseline samples are collected at recruitment with follow up at 6 months and then annually until the age of 7 years.

Results: To date, 80 infants (Male n=41) have been enrolled in the study, mean age at recruitment 17.3 weeks (S.D.10 weeks). Initial feeding and medical questionnaires have been completed by 91% of the participants and up to a year old by 68%. Initial DNA, urine and stool samples have been obtained from 82% of participants, with blood samples from 69%. HLA class II analysis of the first 62 participants showed that 6% have the highest risk genotype and 24% have intermediate risk profiles. Analysis of longitudinal serum samples for the presence markers associated with autoimmunity is ongoing.