Problematic severe asthma in children treated at high altitude: tapering the dose while improving control.

BACKGROUND: Multidisciplinary treatment at high altitude is a possible treatment option for problematic severe asthma (PSA) in children. This management can result in the tapering of inhaled corticosteroids. AIM: Our aim was to analyze the effect of multidisciplinary treatment at high altitude, notably the ability to taper corticosteroids. To get an insight into possible factors influencing tapering, we examined whether demographic variables, disease control and quality of life at treatment entrance could predict the tapering of corticosteroids. METHODS: This prospective open-phase cohort study analyzed the data of 43 children aged 8-17 years referred to a specialized high altitude treatment centre. Lung function (FEV1, FEV1/VC), inflammation (FeNO), medication level, asthma control (ACT) and quality of life [PAQLQ(S)] were evaluated on admission and at discharge. RESULTS: Thirty-two (74%) children fulfilled PSA criteria. Three (7%) children used daily oral steroids. After 72 ± 30 (mean ± SD) days of treatment, the mean dosage of inhaled corticosteroids (ICS) could be significantly reduced from 1315 µg ± 666 budesonide equivalent to 1132 µg ± 514. Oral steroid maintenance therapy could be stopped in all patients. FeNO, asthma control and quality of life improved (p < 0.001) from admission to discharge; FEV1 was in the normal range on both occasions. Apart from ICS levels at entrance, multiple regression analyses did not show any associated factor predicting the reduction of ICS dosage during treatment. CONCLUSION: The results indicate that high altitude treatment may be a treatment option for children with PSA, but it is not possible to predict ICS tapering off from health status variables at treatment entrance.

TBX4 mutations (small patella syndrome) are associated with childhood-onset pulmonary arterial hypertension.

BACKGROUND: Childhood-onset pulmonary arterial hypertension (PAH) is rare and differs from adult-onset disease in clinical presentation, with often unexplained mental retardation and dysmorphic features (MR/DF). Mutations in the major PAH gene, BMPR2, were reported to cause PAH in only 10-16% of childhood-onset patients. We aimed to identify more genes associated with childhood-onset PAH. METHODS: We studied 20 consecutive cases with idiopathic or heritable PAH. In patients with accompanying MR/DF (n=6) array-comparative genomic hybridisation analysis was performed, with the aim of finding common deletion regions containing candidate genes for PAH. Three patients had overlapping deletions of 17q23.2. TBX2 and TBX4 were selected from this area as candidate genes and sequenced in all 20 children. After identifying TBX4 mutations in these children, we subsequently sequenced TBX4 in a cohort of 49 adults with PAH. Because TBX4 mutations are known to cause small patella syndrome (SPS), all patients with newly detected TBX4 mutations were screened for features of SPS. We also screened a third cohort of 23 patients with SPS for PAH. RESULTS: TBX4 mutations (n=3) or TBX4-containing deletions (n=3) were detected in 6 out of 20 children with PAH (30%). All living patients and two parents with TBX4 mutations appeared to have previously unrecognised SPS. In the adult PAH-cohort, one TBX4 mutation (2%) was detected. Screening in the cohort of (predominantly adult) SPS patients revealed no PAH. CONCLUSIONS: These data indicate that TBX4 mutations are associated with childhood-onset PAH, but that the prevalence of PAH in adult TBX4 mutation carriers is low.