NCGS is characterized by gastrointestinal symptoms such as bloating, diarrhoea, weight loss, and abdominal pain. The symptoms can be similar to irritable bowel syndrome (IBS), making it difficult sometimes to differentiate between the two. There can also be extra-intestinal symptoms such as myalgia, bone pain, tiredness, headache, tingling of the extremities, leg or arm numbness and eczema.

Children with NCGS mainly have gastrointestinal symptoms such as abdominal pain, chronic diarrhoea without weight loss. Less frequently, they present with extra-intestinal manifestations, including fatigue and attention-deficit disorders. Currently, it is difficult to know how common this condition is in the paediatric population, but in the adult population, it is thought to be possibly more common than coeliac disease itself.

Symptoms can occur within hours or days of ingesting gluten, and disappear when gluten is removed from the diet.

It is not clear how gluten causes this. Patients do not have positive coeliac serology. They will have negative transglutaminase and deamidated gliadin peptide and endomysial antibodies. Interestingly, they often have positive antigliadin antibodies which are no longer in common use as they lack specificity and sensitivity. (The antigliadin antibodies are different to the newer deamidated gliadin peptide)

Patients also do not have an abnormal small bowel biopsy if this happens to have been done.
It is important that other conditions which can present with similar symptoms be excluded. These include wheat allergy and IBS. Sometimes, the improvement in symptoms when gluten is removed, is actually due to FODMAP foods (fermentable oligo- and disaccharides, monosaccharides and polyols). This group includes a wide range of foods. They include fruit such as apples, pears, watermelon, tinned fruit in their natural juice, lactose containing foods such as milk, cheeses, yoghurt, cereals when consumed in large amounts such as bread, pasta, biscuits, crackers, and vegetables such as asparagus, beetroot, Brussel sprouts, broccoli, cabbage and onions.

It is recommended that all immediate family members be tested regardless of whether they have symptoms or not, because having a family member with the disease is the strongest risk factor for disease development. (HLA DQ positivity is the second strongest risk factor) The risk that another family member also has coeliac disease is about 10%. Not uncommonly, family members may have nonspecific symptoms such as irritable bowel syndrome which might actually be due to coeliac disease.

If the tests come back negative, this only tells you that they are unlikely to currently have coeliac disease, but they could still develop it in the future, and may require retesting. Infants who have not been introduced to solids, and young children need not be tested until they are older (approx.) three to four years of age, unless they have symptoms.

Most often this is due to inadvertent exposure to gluten, and it is often beneficial to have further dietetic evaluation to rule this out as a cause. Sometimes it is due to a secondary lactose intolerance which is temporary. Once the lining of the bowel and the villi have started to heal with institution of the gluten free diet, lactose intolerance should improve and a lactose free diet could be liberalized after a few months.

Internationally, the Codex standard for a low gluten free diet is less than 20 parts per million (ppm)  of gluten as a safe level for children with coeliac disease. This is a very small amount! less than crumbs! For children, it is also recommended that oats be avoided, because of the risk of cross contamination that can occur. Flour mills that process oats often process wheat flour as well.

There are circumstances when perhaps the parents of your patient have already empirically placed their child gluten free without having a small bowel biopsy performed and have found an improvement in their child’s symptoms. This could be due to their child genuinely having coeliac disease. But other possibilities exist, such as wheat intolerance, a problem with FODMAP foods (which commonly have gluten in them). They may have an irritable bowel type syndrome. It could also be co-incidental or there could be a placebo effect.

Normally we would recommend a gluten challenge to definitively diagnose coeliac disease. We would also do HLA DQ2 and 8 testing to determine if they are at genetic risk for coeliac disease, because if they lack the DQ 2 or 8 alleles, then it becomes highly unlikely that they have coeliac disease or will develop it. The DQ2 and 8 testing can be done even if the patient is gluten free. Doing coeliac serology (tTG-IgA or DGP) while they have been off gluten is not useful, unless this has happened within the past few weeks. The planning of a gluten challenge needs to be done in conjunction with discussing it with your paediatric gastroenterologist, so that a date for doing the small bowel biopsy can be tentatively arranged, in order to minimize the duration of gluten exposure.

If the patient shows a positive DQ2 or 8 allele, then they should undergo a gluten challenge. The duration of the challenge varies, but we would generally recommend (in children) 1-3 slices of bread/day or the equivalent, depending on their age, for at least 4 weeks. Sometimes the return of symptoms can be very rapid, but sometimes it can be delayed, and so you would need at least 4 weeks of symptoms before considering a biopsy. Some children are not able to continue with the challenge because their symptoms become too severe, and the challenge has to be stopped after discussion with your gastroenterologist.

Currently coeliac serological testing is not reliable enough to eliminate the need for small bowel biopsy. Recent guidelines from the European Society for Paediatric Gastroenterology and Hepatology and Nutrition (ESPGHAN), have recommended that if the TTG-IgA is >10XULN, and EMA +ve, and HLA DQ2 or 8 +ve, and history is consistent, then a small bowel biopsy is not required. This has not however been followed by USA/Canada and some parts of Australia currently. The ESPGHAN do recommend that these guidelines are dependent on the reliability of local testing.

However, these guidelines may be adopted sometime in the future, but studies of our local assays need to be performed, to determine if the ULN values are going to be consistently reliable. We need to be mindful that coeliac disease is a lifelong condition, and therefore it is very important that the diagnosis is established with certainty.