Examine the genotype-phenotype relationship in Japanese congenital central hypoventilation syndrome (CCHS) patients and estimate the incidence of CCHS in Japan. Subjects were 92 Japanese patients with PHOX2B mutations; 19 cases carried 25 polyalanine repeat expansion mutations (PARMs); 67 cases carried 26 or more PARMs; and 6 had non-PARMs (NPARMs). We collected clinical data in all patients and estimated the development or intelligent quotients only in the patients carrying 25 PARM. The estimated incidence of CCHS was greater than one case per 148 000 births. Polyhydramnios was observed in three cases. Twelve infants exhibited depressed respiration at birth. In 19 cases carrying 25 PARM, the male-to-female ratio was ~3, no cases had Hirschsprung disease; 7 cases (37%) developed hypoventilation after the neonatal period, and 8 cases (42%) had mental retardation. In other 73 cases carrying 26 or more PARMs or NPARMs, male-to-female ratio was equal; patients frequently complicated with Hirschsprung disease and constipation, and all patients presented with hypoventilation in the neonatal period. Clinical symptoms were severe in most patients carrying long PARMs and NPARMs. In 25 PARM, additional genetic and/or epigenetic factors were required for CCHS development and male sex is likely a predisposing factor. The patients carrying 25 PARM frequently had mental retardation likely because they were not able to receive appropriate ventilation support following a definitive diagnosis owing to subtle and or irregular hypoventilation. Molecular diagnosis provides a definitive diagnosis and enables to receive appropriate ventilator support.

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Preterm infants may develop acute systemic hypotension that responds to glucocorticoid therapy, but not to volume loading or vasopressors, during the postnatal period. This condition is termed late-onset circulatory collapse (LCC) that develops a few weeks after birth in relatively stable infants. LCC may cause periventricular leukomalacia, periventricular necrosis in the white matter. The aim of this study was to identify the clinical characteristics of LCC. We retrospectively reviewed the clinical data of infants with LCC. Among 41 infants born at < 29 weeks of gestation between 2010 and 2014, we identified 14 infants (median gestational age 25.6 weeks) with LCC. All infants were stable before the acute onset of circulatory collapse at a median age of 21 days, which is characterized by the decreased physical activity, systolic blood pressure (12 mmHg decrease), urine output (76% decrease), and serum sodium level (4 mEq/L decrease), and the increased resistance index in the cerebral and renal arteries on Doppler ultrasonography. Both left ventricular dimension and contraction were well preserved. Three infants developed hyperkalemia. The median time from the initial hydrocortisone dose to improvements was 4 h (interquartile range 3-5 h). Hydrocortisone therapy was effective, but had to be withdrawn slowly to prevent relapse. The median duration of hydrocortisone therapy was 23 days. There was no evidence of periventricular leukomalacia in any of the infants. None of the infants developed adrenal insufficiency during the follow-up period. During the acute stage of LCC, the main priority is the early initiation of glucocorticoid therapy.

Previous studies have highlighted the importance of confirming the position of an umbilical venous catheter (UVC) tip by an ultrasound (US) examination. However, methods for preventing insertion into the portal circulation under US guidance have not yet been established. We report 15 cases in which a UVC was successfully passed through the ductus venosus by compressing the upper abdomen near the portal sinus of the liver to align the umbilical vein and ductus venosus under US guidance. The UVC was inserted into the correct position in 14 of the 15 neonates (93%) without complications.