We describe four unrelated children who were referred to two tertiary referral medical genetics units between 1991 and 2005 and who are affected with juvenile polyposis of infancy. We show that these children are heterozygous for a germline deletion encompassing two contiguous genes, PTEN and BMPR1A. We hypothesize that juvenile polyposis of infancy is caused by the deletion of these two genes and that the severity of the disease reflects cooperation between these two tumor-suppressor genes.

This 3-month study in 96 constipated children aged 6 months to 3 years confirms the long-term tolerance of PEG 4000 in pediatrics and indicates a PEG efficacy similar to or greater than that of lactulose.

Background-Susceptibility to coeliac disease is strongly associated with particular HLA class II alleles. However, non-HLA genetic factors are likely to be required for the development of the disease. Among candidate genes is the CTLA-4 (cytotoxic T lymphocyte associated) gene located on chromosome 2q33 in humans, which encodes a cell surface molecule providing a negative signal for T cell activation. Aims-To investigate CTLA-4 exon 1 polymorphism (position 49 A/G) in patients with coeliac disease. Patients-101 patients with coeliac disease and 130 healthy controls.Methods-Allele specific hybridisation and restriction enzyme digestion of polymerase chain reaction amplified genomic DNA. Results-The A allele of the CTLA-4 position 49 polymorphism was found on 82.2% of chromosomes in patients with coeliac disease compared with 65.8% in controls (p<0.0001), mostly in the homozygous form (68.3% in patients versus 47.7% in controls; odds ratio (OR) 2.36, 95% confidence interval (CI) 1.37 to 4.06, p=0.002). Four patients only had the G/G genotype compared with 21 controls (OR 0.21, CI 10.07 to 0.64, p=0.002). These diVerences were maintained when subjects were stratified according to the HLA class II phenotype, in particular when patients and controls were matched for the presence of the predisposing HLA DQB1*02 (DQ2) allele or HLA-DQA1*0501/ DQB1*02 heterodimer. Conclusion-The CTLA-4 gene polymorphism is a non-HLA determinant that predisposes to coeliac disease. Whether it directly contributes to disease susceptibility or represents a marker for a locus in linkage disequilibrium with CTLA-4 needs further investigation.

Background: Data on the proton pump inhibitor lansoprazole in paediatric patients are limited. Aim: To investigate the pharmacokinetics, optimal dosage and efficacy of lansoprazole in paediatric patients. Methods: A 24‐h gastric pH recording and a pharmacokinetic study were performed after 7 days of lansoprazole, 17 mg/m2, in 23 patients with reflux oesophagitis (median age, 3.5 years). Response was defined as pH > 3 for > 65% of the recording. The dosage was doubled in non‐responders. Patients with no response on day 14 were excluded. Responders underwent endoscopy after 4 weeks on the response‐inducing dosage; abnormal findings led to a repeat endoscopy after four additional weeks. Results: Nine patients responded to 17 mg/m2 and six to 30.3 mg/m2. On day 7, time with pH > 3 was significantly correlated with the area under the plasma concentration–time curve (P=0.003). The area under the plasma concentration–time curve was significantly greater in the nine responders to 17 mg/m2 than in the 14 other patients. Pharmacokinetic parameters were similar in responders and non‐responders to the higher dose. After 4 weeks, oesophagitis was healed in 80% of responders. Adverse events occurred in three patients and required treatment discontinuation in one. Conclusions: Lansoprazole is effective and safe in children. The optimal starting dosage is 30 mg/m2 or 1.4 mg/kg.