Recurrent pneumonia in three patients with MECP2 duplication syndrome with aspiration as the possible cause.

INTRODUCTION: Methyl-CpG binding protein 2 gene (MECP2) is located on the X chromosome (Xq28) and is important for nervous and immune system functioning. Patients with MECP2 duplication syndrome (MDS) have recurrent respiratory infections (RRIs). Although RRIs often occur with MDS because some patients with MDS also have hypoimmunoglobulinemia and duplication of the interleukin-1-receptor-associated kinase-1 gene (IRAK1), which is also located on Xq28, the phenotype of IRAK1 duplication in patients with MDS remains unclear. METHODS: The clinical course of three patients with MDS who underwent laryngotracheal separation (LTS) at two institutions was summarized. RESULTS: Three patients with MDS were identified to have recurrent pneumonia characteristic of aspiration pneumonia, sometimes requiring artificial ventilation therapy; they had no other bacterial infections. After LTS, they rarely had pneumonia. In MDS, MECP2 expression increased two-fold naturally, while IRAK-1 expression showed no difference compared with a healthy subject. CONCLUSIONS: Since RRIs in MDS are thought to be caused by aspiration and not susceptibility to infection previously estimated to be major complication, the evaluation of aspiration is recommended for RRIs for better management of MDS.

A case of congenital fiber-type disproportion syndrome presenting dilated cardiomyopathy with ACTA1 mutation.

BACKGROUND: Actin, alpha, skeletal muscle 1 (ACTA1) is one of the causative genes of nemaline myopathy (NM) and congenital fiber-type disproportion (CFTD). CFTD is characterized by type 1 fiber atrophy and distinguished from NM in the absence of rods. Eight patients with CFTD, including one patient with dilated cardiomyopathy (DCM), have previously been reported. Herein, we report the case of a 10-year-old boy presenting with CFTD and DCM. METHODS: We performed exome sequencing and analyzed the effect of Met327Lys mutations on cultured C2C12 muscle cells compared with that seen in the wild type (WT, ACTA1) and previously identified Asp294Val mutations associated with a severe phenotype of CFTD without cardiomyopathy. RESULTS: Exome sequencing revealed a de novo mutation, c.980 T > A, p.(Met327Lys), in ACTA1 (NM_001100.4). C2C12 cells transfected with the WT plasmid expressed ACTA1 in the nucleus and cytoplasm. Cells with the Asp294Val mutant showed needle-like structures in the cytoplasm, whereas the expression of the Met327Lys mutant resulted in few aggregations but many apoptotic cells. CONCLUSION: Apoptosis induced in Met327Lys-transfected muscle cells supports the pathogenicity of the mutation and can be implicated as one of the histopathological features associated with CFTD, as in NM.