Australian research highlights coeliac disease prevalence in first-degree relatives

By Michael Doris MB BS

Australian research supports active case finding among first-degree relatives of people diagnosed with coeliac disease, consistent with overseas guidelines.

In the Australian-first study, conducted at the Wesley Research Institute in Brisbane and published in the Medical Journal of Australia, researchers estimated the prevalence of coeliac disease in first-degree relatives of people diagnosed with coeliac disease. Acknowledging the benefits in the early diagnosis of coeliac disease, the researchers noted that no relevant Australian data on first-degree relatives were available.

In their prospective observational study, 202 first-degree relatives (children, siblings or parents) of 134 people with coeliac disease were invited to undergo screening: 62 participants were under 18 years of age and 140 were 18 years of age or older.

Screening was undertaken with HLA-DQ2/8/7 polymerase chain reaction genotyping for coeliac disease risk alleles. Participants with positive results underwent subsequent serological testing for anti-tissue transglutaminase immunoglobulin A (anti-tTG IgA) and anti-deamidated gliadin peptide immunoglobin G (anti-DGP IgG). Where possible, small bowel biopsies were performed for patients with high serum anti-tTG IgA or anti-DGP IgG levels.

Coeliac disease susceptibility haplotypes were observed in 173 (86%) of the 202 participants. Serology results were positive for 16 participants (10 children and six adults), with small bowel biopsies being performed on seven of the 10 children and three of the six adults. Anatomical changes, such as villous atrophy, crypt hyperplasia and intraepithelial lymphocytosis, were detected in all seven of the children biopsied and two of the adults biopsied.

These findings yielded an estimated prevalence of coeliac disease of 11% for biopsy-confirmed disease in children and 1.4% in adults, as well as a prevalence of 14% for children with coeliac disease susceptibility haplotypes.

Dr Robert Anderson, President of the International Society for the Study of Celiac Disease and Consultant Gastroenterologist at the Mackay Base Hospital, Mackay, explained, ‘It is known that close family members of patients newly diagnosed with coeliac disease in Australia are at about six-times higher risk for coeliac disease, which is in line with European and American studies and supports recommendations to offer serology testing to first-degree relatives.’

‘The study limited endoscopy to family members with elevated coeliac serology but, in general clinical practice, endoscopic duodenal biopsy while gluten is regularly consumed is recommended as the “gold standard” to rule out coeliac disease,’ he said.

‘Unrecognised coeliac disease is common and family screening using coeliac serology is one of the more efficient strategies to address this continuing public health challenge,’ he added.

Med J Aust 2023; doi: 10.5694/mja2.52105.