Population-based frequency of surfactant dysfunction mutations in a native Chinese cohort.

BACKGROUND: Rare mutations in surfactant-associated genes contribute to neonatal respiratory distress syndrome. The frequency of mutations in these genes in the Chinese population is unknown. METHODS: We obtained blood spots from the Guangxi Neonatal Screening Center in Nanning, China that included Han (n=443) and Zhuang (n=313) ethnic groups. We resequenced all exons of the surfactant proteins-B (SFTPB), -C (SFTPC), and the ATP-binding cassette member A3 (ABCA3) genes and compared the frequencies of 5 common and all rare variants. RESULTS: We found minor differences in the frequencies of the common variants in the Han and Zhuang cohorts. We did not find any rare mutations in SFTPB or SFTPC, but we found three ABCA3 mutations in the Han [minor allele frequency (MAF)=0.003] and 7 in the Zhuang (MAF=0.011) cohorts (P=0.10). The ABCA3 mutations were unique to each cohort; five were novel. The collapsed carrier rate of rare ABCA3 mutations in the Han and Zhuang populations combined was 1.3%, which is significantly lower than that in the United States (P<0.001). CONCLUSION: The population-based frequency of mutations in ABCA3 in south China newborns is significantly lower than that in United States. The contribution of these rare ABCA3 mutations to disease burden in the south China population is still unknown.

Minoxidil-associated anorexia in an infant with refractory hypertension.

Minoxidil is a potent antihypertensive used as an adjunctive agent in refractory hypertension. It exerts an antihypertensive effect through two mechanisms: selective arterial vasodilation by activation of potassium channels in the vascular smooth muscle and stimulation of carotid and aortic baroreceptors, leading to downstream release of renin and norepinephrine. Although frequently cited in reviews of antihypertensive agents, limited data about the use of minoxidil in neonates are available. We describe an infant girl, born at 35 weeks of gestation, who was diagnosed with idiopathic hypertension after extensive diagnostic evaluation. Adequate blood pressure control was not achieved with captopril, amlodipine, and clonidine. Oliguria secondary to captopril and rapid-onset congestive heart failure due to persistent hypertension led to the introduction of intravenous agents labetalol and nitroprusside. Although adequate blood pressure control was achieved, attempts to transition back to oral agents were unsuccessful, prompting the use of minoxidil as an alternative agent. Although good blood pressure control was achieved, the infant's oral intake plummeted from 210 to 63 ml/kg/day. The anorexia quickly resolved after stopping minoxidil, and she was discharged home at 5 months of age receiving propranolol, amlodipine, and doxazosin. Use of the Naranjo adverse drug reaction probability scale indicated a definite relationship (score of 10) between the patient's development of anorexia and minoxidil therapy. To our knowledge, there have been no previous reports of minoxidil-associated anorexia in preterm or term infants. Clinicians should be aware that anorexia is a possible adverse effect of minoxidil in this patient population when initiating the drug in similar patients.