Mutations in RPSA and NKX2-3 link development of the spleen and intestinal vasculature

Idiopathic intestinal varicosis is a developmental disorder defined by dilated and convoluted submucosal veins in the colon or small bowel. A limited number of families with idiopathic intestinal varices has been reported, but the genetic cause has not yet been identified. We performed whole‐exome and targeted Sanger sequencing of candidate genes in five intestinal varicosis families. In four families, mutations in the RPSA gene were found, a gene previously linked to congenital asplenia. Individuals in these pedigrees had intestinal varicose veins and angiodysplasia, often in combination with asplenia. In a further four‐generation pedigree that only showed intestinal varicosities, the RPSA gene was normal. Instead, a nonsense mutation in the homeobox gene NKX2‐3 was detected which cosegregated with the disease in this large family with a LOD (logarithm of the odds) score of 3.3. NKX2‐3 is a component of a molecular pathway underlying spleen and gut vasculature development in mice. Our results provide a molecular basis for familial idiopathic intestinal varices. We provide evidence for a relationship between the molecular pathways underlying the development of the spleen and intestinal mucosal vasculature that is conserved between humans and mice. We propose that clinical management of intestinal varices, should include assessment of a functional spleen.

Efficacy of Home Telemonitoring versus Conventional Follow-up: A Randomized Controlled Trial among Teenagers with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Conventional follow-up of teenagers with inflammatory bowel diseases [IBD] is done during scheduled outpatient visits regardless of how well the patient feels. We designed a telemonitoring strategy for early recognition of flares and compared its efficacy with conventional follow-up.

METHODS

We used a multicentre randomized trial in patients aged 10-19 years with IBD in clinical remission at baseline. Participants assigned to telemonitoring received automated alerts to complete a symptom score and send a stool sample for measurement of calprotectin. This resulted in an individual prediction for flare with associated treatment advice and test interval. In conventional follow-up the health check interval was left to the physician's discretion. The primary endpoint was cumulative incidence of disease flares. Secondary endpoints were percentage of participants with a positive change in quality-of-life and cost-effectiveness of the intervention.

RESULTS

We included 170 participants [84 telemonitoring; 86 conventional follow-up]. At 52 weeks the mean number of face-to-face visits was significantly lower in the telemonitoring group compared to conventional follow-up [3.6 vs 4.3, p < 0.001]. The incidence of flares [33 vs 34%, p = 0.93] and the proportion of participants reporting positive change in quality-of-life [54 vs 44%, p = 0.27] were similar. Mean annual cost-saving was €89 and increased to €360 in those compliant to the protocol.

CONCLUSIONS

Telemonitoring is as safe as conventional follow-up, and reduces outpatient visits and societal costs. The positive impact on quality-of-life was similar in the two groups. This strategy is attractive for teenagers and families, and health professionals may be interested in using it to keep teenagers who are well out of hospital and ease pressure on overstretched outpatient services.

TRIAL REGISTRATION

NTR3759 [Netherlands Trial Registry].

Pediatric Achalasia in the Netherlands: Incidence, Clinical Course, and Quality of Life

OBJECTIVE

To assess incidence and clinical course of Dutch patients with achalasia diagnosed before 18 years of age as well as their current symptoms and quality of life (QoL).

STUDY DESIGN

Retrospective medical chart review and a cross-sectional study assessing current clinical status using the Eckardt score and reflux disease questionnaire. General QoL was measured using Kidscreen-52 for patients <18 years of age or to 36-Item Short Form Health Survey for patients ≥18 years of age.

RESULTS

Between 1990 and 2013, 87 children (mean age 11.4 ± 3.4 years, 60% male) diagnosed with achalasia in the Netherlands were included. Mean incidence was 0.1/100,000/y (range 0.03-0.21). Initial treatment was pneumodilation (PD) in 68 (79%) patients and Heller myotomy (HM) in 18 (21%) patients. Retreatment was required more often after initial PD compared with initial HM (88% vs 22%; P < .0001). More complications of initial treatment occurred after HM compared with PD (55.6% vs 1.5%; P < .0001). Three esophageal perforations were seen after HM (16.7%), 1 after PD (1.5%). Sixty-three of 87 (72%) patients were prospectively contacted. Median Eckardt score was 3 (IQR 2-5), with 32 patients (44.5%) having positive scores suggesting active disease. Reflux disease questionnaire scores were higher after initial HM vs PD (1.71 [0.96-2.90] vs 0.58 [0-1.56]; P = .005). The 36-Item Short Form Health Survey (n = 52) was lower compared with healthy population norms for 7/8 domains. Kidscreen-52 (n = 20) was similar to population norms.

CONCLUSIONS

Pediatric achalasia is rare and relapse rates are high after initial treatment, especially after pneumodilation, but with more complications after HM. Symptoms often persist into adulthood, without any clinical follow-up. QoL in adulthood was decreased.

Quantitative contribution of NHE2 and NHE3 to rabbit ileal brush-border Na+/H+ exchange

Intestinal neutral NaCl absorption, which is made up of brush-border (BB) Na+/H+ exchange linked to BB Cl-/HCO3- exchange, is up- and downregulated as part of digestion and diarrheal diseases. Glucocorticoids stimulate ileal NaCl absorption and BB Na+/H+ exchange. Intestinal BB contains two Na+/H+ exchanger isoforms, NHE2 and NHE3, but their relative roles in rabbit ileal BB Na+/H+ exchange has not been determined. A technique to separate the contribution of NHE2 and NHE3 to ileal BB Na+/H+ exchange activity was standardized by using an amiloride-related compound, HOE-694. Under basal conditions, both NHE2 and NHE3 contribute approximately 50% to ileal Na+/H+ exchange. Glucocorticoids (methylprednisolone) increase BB Na+/H+ exchange (2.5 times) but increase only ileal NHE3 activity (4.1 times), without an effect on NHE2 activity. Thus ileal BB Na+/H+ exchange in animals treated with glucocorticoids is 69% via NHE3. A quantitative Western analysis for NHE3 was developed, using as an internal standard a fusion protein of the COOH-terminal 85 amino acids of NHE3 and maltose binding protein. Glucocorticoid treatment increased the amount of BB NHE3. The quantitative Western analysis showed that NHE3 makes up 0.018% of ileal BB protein in control rabbits and 0.042% (2.3 times as much) in methylprednisolone-treated rabbits. Methylprednisolone treatment did not alter the amount of ileal BB NHE2 protein. NHE3 turnover number was estimated to be 458 cycles/s under basal conditions and 708 cycles/s in glucocorticoid-treated ileum. Thus methylprednisolone stimulates ileal BB Na+/H+ exchange activity only by an effect on NHE3 and not on NHE2; it does so primarily by increasing the amount of BB NHE3, although it also increases the NHE3 turnover number.