Somatic and germline mosaicism for an X-linked dominant mutation in PHEX may mimic autosomal dominant inheritance.

Objective We recently reported cases of adipsic hypernatremia caused by autoantibodies against the subfornical organ in patients with hypothalamic‐pituitary lesions. This study aimed to clarify the clinical features of newly identified patients with adipsic hypernatremia whose sera displayed immunoreactivity to the mouse subfornical organ. Design Observational cohort study of patients diagnosed with adipsic hypernatremia in Japan, United States, and Europe. Methods The study included 22 patients with adipsic hypernatremia but without overt structural changes in the hypothalamic‐pituitary region and congenital disease. Antibody response to the mouse subfornical organ was determined using immunohistochemistry. The clinical characteristics were compared between the patients with positive and negative antibody responses. Results Antibody response to the mouse subfornical organ was detected in the sera of 16 patients (72.7%, female/male ratio, 1:1, 12 pediatric and 4 adult patients). The prolactin levels at the time of diagnosis were significantly higher in patients with positive subfornical organ (SFO) immunoreactivity than in those with negative SFO immunoreactivity (58.9 ± 33.5 vs. 22.9 ± 13.9 ng/ml, p < .05). Hypothalamic disorders were found in 37.5% of the patients with positive SFO immunoreactivity. Moreover, six patients were diagnosed with rapid‐onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation/neural tumor syndrome after the diagnosis of adipsic hypernatremia. Plasma renin activity levels were significantly higher in patients with serum immunoreactivity to the Nax channel. Conclusions The patients with serum immunoreactivity to the SFO had higher prolactin levels and hypothalamic disorders compared to those without the immunoreactivity. The clinical characteristics of patients with serum immunoreactivity to the subfornical organ included higher prolactin levels and hypothalamic disorders, which were frequently associated with central hypothyroidism and the presence of retroperitoneal tumors.

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A one-year-and-nine-month-old Japanese boy was admitted with hypertriglyceridemia (fasting triglycerides 2548 mg/dL). After close examination, he was diagnosed with lipoprotein lipase (LPL) deficiency (compound heterozygous) and was immediately started on a fat-restricted dietary therapy. He responded well to the regimen (1200 kcal/day, 20 g fat/day) and his triglycerides decreased to 628 mg/dL within 7 days of starting the dietary therapy. It was decided to manage his illness without using any drugs because he was still an infant and responded well to a fat-restricted diet. During his hospital stay, dietitians provided him with nutritional counseling using a food exchange list, which was designed to easily calculate the fat content by including foods that are commonly served. His family quickly learned the skills to prepare a fat-restricted diet. Moreover, since dietary restrictions may have impaired the child's growth and development, the dietitians continued to intervene regularly after the child was discharged from the hospital. The dietitians confirmed that the patient was receiving nutritional intake appropriate for his growth and discussed the dietary concerns in his daily life and how to participate in school events that involved eating and drinking. Nutritional counseling was provided every 3-4 months from disease onset to age 23 years, except for a 14-month break at age 20 years. The patient grew up without developing acute pancreatitis, a serious complication of LPL deficiency. The long-term intervention of dieticians is necessary to achieve a balance between living on a strict diet for disease management and ensuring appropriate nutritional intakes for growth/development.

Type 1 diabetes mellitus (T1DM) and poor glycemic control are risk factors for severe coronavirus disease 2019 . Sotrovimab can treat mild-to-moderate COVID-19 in patients at a high risk of progression to severe COVID-19. However, its safety and efficacy in T1DM patients remain to be elucidated. We report the case of a 12-year-old patient who was treated with sotrovimab for COVID-19 immediately after treatment for diabetic ketoacidosis (DKA) due to new-onset T1DM. He presented with nausea and sore throat and was diagnosed with severe DKA and COVID-19. A productive cough and sputum developed after admission. On the 3rd day of admission, the DKA resolved, and sotrovimab was administered to prevent exacerbation of COVID-19. Although the blood glucose levels increased after the administration of sotrobimab, there was no recurrence of DKA.Hyperglycemia may be a sotrovimab-related adverse event in T1DM patients. Nevertheless, the benefits of sotrovimab treatment may far outweigh the potential risks. Thus, sotrovimab was considered safe for patients with T1DM immediately after treatment of severe DKA.