Hypertension and brachydactyly syndrome (HTNB) with short stature is an autosomal-dominant disorder. Mutations in the PDE3A gene located at 12p12.2-p11.2 were recently identified in HTNB families. We found a novel heterozygous missense mutation c.1336T>C in exon 4 of the PDE3A gene in a Japanese family with multiple HTNB patients. This mutation was found to be completely linked to the family members who inherited this condition. The mutation, resulting in p.Ser446Pro, was located within the cluster region of reported mutations. This mutation may also affect the phosphodiesterase activity of PDE3A to reduce the cyclic AMP level in the cell and thereby influencing the development of limbs and the function of the cardiovascular system.

A de novo 3-bp deletion (179-181delGTG) was identified at exon 3 of the PTPN11 gene in a female infant with severe Noonan phenotype including hydrops fetalis and juvenile myelomonocytic leukemia. Since the 3-bp deletion is predicted to result in loss of the 60th glycine in the N-SH2 domain that is directly involved in the intramolecular interaction between the N-SH2 and the PTP domains of the PTPN11 protein, this mutation would disrupt the N-SH2/PTP binding in the absence of a phosphopeptide, leading to an excessive phosphatase activity. The results expand the spectrum of PTPN11 mutations in Noonan syndrome (NS), and suggest that a PTPN11 mutation leads to a wide range of clinical features of Noonan syndrome.

This study is direct evidence of no transmission of rotavirus vaccine strains between vaccinated infants and unvaccinated infants in close proximity within a NICU.

Doxapram hydrochloride, a respiratory stimulant, has several undesirable side effects during high-dose administration, including second-degree atrioventricular (AV) block and QT prolongation. In Japan, this drug is contraindicated for newborn infants. Recent studies, however, have demonstrated the efficacy and safety of doxapram therapy for apnea of prematurity (AOP) using lower doses than those previously tested. As a result, approximately 60% of Japanese neonatologists continue to use this drug. This study used surface ECG recordings to assess the cardiac safety of low-dose doxapram hydrochloride (0.2 mg/kg/h) in fifteen premature very-low-birth-weight infants with idiopathic AOP. Cardiac intervals and number of apnea episodes were compared before and after drug administration. Low-dose doxapram hydrochloride resulted in approximately 90% reduction in the frequency of apnea without side effects. None of the infants developed QT or PR prolongation, arrhythmia, or other conduction disorders. In addition, there was no change in the slope of QT/RR before versus after administration of doxapram hydrochloride. We conclude that low-dose administration of doxapram hydrochloride did not have any undesirable effects on myocardial depolarization and repolarization.

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