Idiopathic pulmonary hemosiderosis associated with Kabuki syndrome.

Kabuki syndrome (KS) is a genetic disorder caused by gene mutations in either lysine-specific methyltransferase 2D (KMT2D) or lysine demethylase 6A (KDM6A). This congenital disorder exhibits characteristic facial features, developmental delays in psychomotor skills, and skeletal abnormalities. Moreover, it is classified as a congenital immunodeficient disorder under the category of combined immunodeficiency, leading to hypogammaglobulinemia and the onset of autoimmune diseases. Here, we present the first case of KS complicated by idiopathic pulmonary hemosiderosis (IPH). The KS patient, a 2-year-old Japanese girl with a history of hypoplastic left heart syndrome and recurrent bacterial infection, developed severe respiratory distress and anemia. She had autoimmune hemolytic anemia and gouty nephropathy. Hemophagocytic macrophages with hemosiderin ingestion were identified in bronchoalveolar lavage fluid, excluding differential diagnoses and leading to the diagnosis of idiopathic pulmonary hemosiderosis. Intravenous prednisolone (2 mg/kg/day) was administered, but symptoms did not improve. However, pulmonary hemorrhage disappeared with methylprednisolone pulse therapy. IPH warrants consideration in cases where individuals with KS manifest idiopathic pneumonia and concurrent anemia.

Prophylactic immunoglobulin therapy for pediatric congenital myotonic dystrophy.

Congenital Myotonic Dystrophy (CMD) is an autosomal dominant hereditary disease caused by mutations in the dystrophia myotonica protein kinase gene. Patients with CMD often exhibit low immunoglobulin (Ig) G levels. While Ig replacement therapy for low IgG levels has been reported in several adult cases, there have been no reports on pediatric patients. This study presents a first pediatric case where Ig replacement therapy effectively eliminated susceptibility to infections. The CMD patient, a 1-year-old Japanese female with a history of premature birth and necrotizing enterocolitis, developed recurrent severe bacterial infections due to hypogammaglobulinemia. Intravenous immunoglobulin (IVIG) (600 mg/kg/month) was administered but failed to maintain sufficient serum trough IgG levels. The dosage was increased to 2 g/kg/month, and later, the treatment shifted to subcutaneous immunoglobulin (SCIG), resulting in a stable serum trough IgG level above 700 mg/dL for one year. The cause of hypogammaglobulinemia in CMD patients remains unclear, but potential mechanisms, including IgG-mediated hypercatabolism by alterations in the neonatal Fc receptor, have been considered. Genetic testing ruled out common variable immunodeficiency, and other potential causes were excluded. The study suggests that higher doses of IVIG or SCIG can effectively prevent severe infections associated with CMD-induced hypogammaglobulinemia in children.

This case report sheds light on the efficacy of immunoglobulin therapy in pediatric congenital myotonic dystrophy (CMD). We anticipate that our findings will have a positive impact on clinical practice by providing insights into the prevention of severe infections associated with CMD-induced hypogammaglobulinemia. This research is of great interest to the readers of the journal as it addresses an unmet need in pediatric CMD management by providing a strategy for successful immunoglobulin therapy for the treatment of pediatric CMD.