Effects of short-term treatment with vibegron for refractory nocturnal enuresis.

BACKGROUND: Long-term nocturnal enuresis treatment leads to stress and lowered self-esteem for children and their parents. This study evaluated the short-term effectiveness and safety of vibegron (50 mg) for children with refractory nocturnal enuresis. METHODS: A retrospective cohort study of children with therapy-resistant enuresis was conducted using data for July to December 2019. Enuresis frequency was recorded during 30 days before and after additional vibegron administration with prior treatment. We assessed the treatment effectiveness based on enuresis frequencies between before and after treatment with vibegron 50 mg. Statistical evaluation was performed using a paired t-test. RESULTS: Among 29 children receiving vibegron, 14 (48.3%) exhibited a partial or complete response to the drug. Enuresis frequencies (mean ± standard deviation [SD]) were, respectively, 15.8 ± 9.2 and 9.5 ± 9.6 before and after treatment with vibegron during the observed 30 days. A statistically significant reduction in enuresis frequency was found (p < 0.001). Moreover, maximum mean±SD morning urine of 200 ± 62.9 mL before treatment with vibegron changed to 232 ± 76.6 mL after treatment. A significant increase in voiding volume in the early morning was found (p < 0.05). No drug-related severe adverse event was found. CONCLUSION: Short-term treatment with vibegron is safe and effective for children with refractory enuresis.

TRPV6 Gene Mutation in a Dizygous Twin With Transient Neonatal Hyperparathyroidism.

Maternal-fetal transport of calcium (Ca2+) is important for bone mineralization in fetal development. Insufficient Ca2+ transport causes transient neonatal hyperparathyroidism (TNHP). Transient receptor potential cation channel, subfamily V, member 6 (TRPV6), has been found to play an important role in the active transport of Ca2+ through the placenta. Recently, TRPV6 gene was found to be the gene responsible for TNHP with severe skeletal undermineralization. To date, only seven cases of TNHP caused by TRPV6 recessive mutations have been reported. We present a case of TNHP caused by TRPV6 gene mutations. A female newborn was hospitalized because of respiratory distress. Marked undermineralization of the skeleton was observed in X-ray imaging. Laboratory examination revealed markedly high PTH and absence of hypercalcemia along with vitamin D deficiency. Her twin brother presented with almost no symptoms. Maternal laboratory findings indicated normocalcemia, but vitamin D deficiency with a high PTH level for the lactation period was observed. We initially diagnosed the patient as having secondary hyperparathyroidism because of maternal vitamin D deficiency. Nevertheless, the reasons underlying the discordant clinical manifestations between the twin siblings remained unclear. Our analysis of TRPV6 gene clarified that the patient had compound heterozygote mutations, which were reported previously (p.Ile223Thr and p.Gly428Arg). Pathologic mutations in TRPV6 gene were not detected in the other sibling. The clinical symptoms in the patient were transient: they resolved during infancy. TNHP caused by TRPV6 gene mutations is a unique disease in terms of its transient pathology in utero and relief after birth.

Novel AVPR2 mutation causing partial nephrogenic diabetes insipidus in a Japanese family.

BACKGROUND: X-linked recessive congenital nephrogenic diabetes insipidus (NDI) is caused by mutations of the arginine vasopressin type 2 receptor gene (AVPR2). More than 200 mutations of the AVPR2 gene with complete NDI have been reported although only 15 mutations with partial NDI has been reported to date. METHODS: We herein report a Japanese kindred with partial NDI. The proband is an 8-year-old boy who was referred to our hospital for nocturnal enuresis. Water deprivation test and hypertonic saline test suggested partial renal antidiuretic hormone arginine vasopressin (AVP) resistance. RESULTS: Analysis of genomic DNA revealed a novel missense mutation (p.L161P) in the patient. The patient's mother was heterozygous for the mutation. Three-dimensional (3-D) modeling study showed that L161P possibly destabilizes the transmembrane domain of the V2 receptor, resulting in its misfolding or mislocalization. CONCLUSIONS: Distinguishing partial NDI from nocturnal enuresis is important. A clinical clue for diagnosis of partial NDI is an incompatibly high level of AVP despite normal serum osmolality.

Intraday glucose fluctuation is common in preterm infants receiving intermittent tube feeding.

BACKGROUND: We previously reported on three preterm infants with blood glucose abnormalities after reaching full enteral feeding. Recently, it has been shown that clinically stable preterm infants may have large fluctuations in blood glucose after the establishment of enteral nutrition. We hypothesized that intraday glucose fluctuation is a common finding in preterm infants, but improves at term post-conceptual age. This report describes a case series. METHODS: From June 2010 to July 2012, 13 preterm infants (29.5 ± 2.1 post-conceptual weeks, 1144 ± 319 g) were enrolled in this study. Continuous glucose monitoring (CGM) was conducted on average at 33.5 ± 1.4 post-conceptual weeks, when they received gastric tube feeding every 3 h in the absence of i.v. glucose supply. RESULTS: Eight infants (62%) had large intraday glucose fluctuation with repeated hyperglycemic (>150 mg/dL) and hypoglycemic (<50 mg/dL) events. In five infants, follow-up CGM at 36-38 weeks post-conceptual age showed more stable glycemic changes without any abnormal glucose levels. CONCLUSIONS: On CGM, in some preterm infants intermittent tube feeding resulted in large intraday glucose fluctuation at 31-35 post-conceptual weeks, but the pattern disappeared before discharge (36-38 post-conceptual weeks).

Fetal Erythroblastosis May Be an Indicator of Neonatal Transient Hyperinsulinism.

BACKGROUND: Small for gestational age and birth asphyxia are associated with neonatal transient hyperinsulinism (THI). Some newborns with THI showed marked erythroblastosis on admission to our neonatal intensive care unit. OBJECTIVE: This study was designed to test our hypothesis that fetal erythroblastosis may be a risk factor for developing THI. METHODS: The records of all babies admitted to our neonatal intensive care unit within 24 h of birth between January 2010 and May 2014, and who were born after 34 weeks of gestation, were retrospectively reviewed. Hyperinsulinism was diagnosed as hypoglycemia concomitant with high serum insulin in babies requiring >6 mg/kg/min intravenous glucose and THI as hyperinsulinism without maternal diabetes or genetic disorders. The following three possible risk factors for THI were evaluated: (1) birth weight z-score, (2) 1-min Apgar score and (3) absolute nucleated red blood cell (aNRBC) count on admission. RESULTS: Of 705 infants, 8 were diagnosed with THI. Multivariate logistic regression analysis revealed that the aNRBC count was the most significant risk factor for THI. The median aNRBC count was 181/µl (interquartile range 0-538/µl), and 8 of 71 infants (11.3%) having an aNRBC count >1,413/µl (90th percentile in this study) had THI. The aNRBC counts in the 8 cases with THI were significantly higher than those in the 5 cases with hyperinsulinism caused by maternal diabetes or genetic disorders. CONCLUSIONS: This study showed that the aNRBC count was strongly associated with subsequent THI. Fetal erythroblastosis, characterized by chronic fetal hypoxia, may be an indicator of perinatal stress sufficient to cause THI.

Expiratory CO2 as the first sign of successful ventilation during neonatal resuscitation.

Three-lead electrocardiography and expired CO2 monitoring were used during positive pressure ventilation of seven non-intubated newborns (gestational age, 31-37 weeks; birthweight, 1503-2885 g). In all cases, adequate CO2 (>15 mmHg) was detected prior to the achievement of stable heart rate (>100 beats/min). The delay between detection of adequate CO2 and improvement of bradycardia ranged from 8 to 73 s (median, 15 s). Inadequate expired CO2 during positive pressure ventilation indicates airway obstruction or poor aeration of the newborn lungs. Thus, positive expiratory CO2 can be the first recognizable sign of successful ventilation during neonatal resuscitation.

Transient neonatal hyperinsulinism with adaptation disorders: a report of three cases.

Transient hyperinsulinism can occur in neonates following exposure to perinatal stress, such as intrauterine growth restriction and birth asphyxia. However, little is known about its pathophysiology and clinical manifestations. We report three neonatal cases of transient severe hyperinsulinism complicated with cardiopulmonary problems, thrombocytopenia, and marked erythroblastosis at birth. All cases showed signs of placental insufficiency, indicating that chronic hypoxia and malnutrition during fetal development might be associated with characteristic clinical features after birth. Perinatal stress-associated hyperinsulinism can be regarded as a systemic syndrome characterized by cardiopulmonary and hematological problems due to fetal chronic hypoxia.

A case of autosomal dominant osteopetrosis type II with a novel TCIRG1 gene mutation.

Osteopetrosis is a rare genetic disorder characterized by increased bone mineral density (BMD) due to osteoclast failure. T-cell immune regulator 1 (TCIRG1) plays crucial roles on osteoclast function, and its mutation causes autosomal recessive osteopetorosis. However, mutations in TCIRG1 have never been identified in autosomal dominant osteopetrosis (ADO). A 3-year-old boy was first presented to the clinic because of spontaneous radius and femur fractures. He has optic atrophy. The areal BMD at the lumbar spine was 1274 g/cm2 (233% of normal). Laboratory tests revealed no remarkable abnormal findings, including anemia, except for extremely elevated serum tartrate-resistant acid phosphatase-5b (14,600 mU/dL). Radiographically, the skull base, pelvis, and vertebrae showed a focal sclerosis. Genetic analysis revealed a novel de novo heterozygous missense mutation (His242Arg). Taken together with the mutation, his mild clinical features were diagnosed as ADO. This case implies that TCIRG1 could become a genetic candidate for ADO in addition to malignant forms such as ARO.

Japanese growth prediction model for prepubertal children with growth hormone deficiency.

BACKGROUND: Individual responses to growth hormone (GH) treatment are variable, and efficacy should be judged in each individual patient. OBJECTIVE: The aim of this study was to develop a prediction model for the growth response of GH treatment in Japanese prepubertal children with GH deficiency. PATIENTS AND METHODS: Pediatric patients with GH deficiency were enrolled. Auxological measurements, markers of GH status, and markers of bone metabolism were measured at baseline and at 3 and 6 months after the start of GH treatment. Correlations with height velocity (HV) at 36 months of GH treatment were calculated. Prediction models were evaluated by multiple regression analysis. RESULTS: The model, which combined the parameters of HV at 3 months, insulin-like growth factor-binding protein 3, standard deviation score, and pyridinoline at 3 months, best predicted HV at 36 months. CONCLUSIONS: This model can accurately predict the first 3 years of growth response after 3 months of GH replacement therapy in prepubertal Japanese children.

[Bone and joint diseases in children. Bisphosphonates in osteogenesis imperfecta].

Osteogenesis imperfecta (OI) is a genetic disorder characterized by fragile bone and reduced bone mineral density. Cyclic intravenous pamidronate is now the most widely used treatment for moderate to severe forms of OI. Oral bisphosphonates provide clinical benefit and convenience to the patients with mild form of OI. Recently, some studies demonstrated that intravenous zolendronate in children with OI is safe in short-term and similarly effective to parmidronate. Optimal dose, duration of treatment and long-term safety of newer bisphosphonates require further investigations.

[Bisphosphonates and other new therapeutic agents for the treatmednt of osteogenesis imperfecta].

Osteogenesis imperfecta (OI) is a genetic disorder characterized by fragile bone and reduced bone mineral density. Cyclic intravenous pamidronate is now the standard treatment for moderate to severe forms of OI, however clinical studies are not yet sufficient to conclude appropriate annual doze and ideal duration of therapy at present time. Oral alendronate is also effective in milder forms of OI. Zoledronic acid has undergone international multicentric clinical trials to examine efficiency and long-term side effects including osteonecrosis of the jaw. Teriparatide (rhPTH1-34) and denosumab (monoclonal antibody against RANK ligand) have the potential for management of OI. Stem cell and gene therapy are currently being actively investigated and may become clinically applicable in the near future.