Five of their 6 cases had TNDM due to paternal uniparental disomy; of these 3 had hyperinsulinism (detectable insulin levels at the time of hypoglycaemia) and 2 had probable hyperinsulinism (undetectable insulin levels, but suppressed ketones at the time of hypoglycaemia, and zresponse to diazoxide therapy. This evidence concerns the gene INS and hyperinsulinism.