Myocardial ultrastructure can augment genetic testing for sporadic dilated cardiomyopathy with initial heart failure

Aims

The aim of the present study was to consider whether the ultrastructural features of cardiomyocytes in dilated cardiomyopathy can be used to guide genetic testing.

Methods and results

Endomyocardial biopsy and whole‐exome sequencing were performed in 32 consecutive sporadic dilated cardiomyopathy patients [51.0 (40.0–64.0) years, 75% men] in initial phases of decompensated heart failure. The predicted pathogenicity of ultrarare (minor allele frequency ≤0.0005), non‐synonymous variants was determined using the American College of Medical Genetics guidelines. Focusing on 75 cardiomyopathy‐susceptibility and 41 arrhythmia‐susceptibility genes, we identified 404 gene variants, of which 15 were considered pathogenic or likely pathogenic in 14 patients (44% of 32). There were five sarcomeric gene variants (29% of 17 variants) found in five patients (16% of 32), involving a variant of MYBPC3 and four variants of TTN. A patient with an MYBPC3 variant showed disorganized sarcomeres, three patients with TTN variants located in the region encoding the A‐band domain showed sparse sarcomeres, and a patient with a TTN variant in encoding the I‐band domain showed disrupted sarcomeres. The distribution of diffuse myofilament lysis depended on the causal genes; three patients with the same TMEM43 variant had diffuse myofilament lysis near nuclei (P = 0.011), while two patients with different DSP variants had lysis in the peripheral areas of cardiomyocytes (P = 0.033).

Conclusions

Derangement patterns of myofilament and subcellular distribution of myofilament lysis might implicate causal genes. Large‐scale studies are required to confirm whether these ultrastructural findings are related to the causative genes.

Epilepsia Partialis Continua as an Early Sign of Anti-Myelin Oligodendrocyte Glycoprotein Antibody-positive Encephalitis

Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been associated with steroid-responsive cortical encephalitis and comorbid generalized epilepsy. A 44-year-old woman developed repeated epilepsia partialis continua (EPC) without generalized seizures and was anti-MOG antibody-positive. Radiological abnormalities were detected in the bilateral medial frontoparietal cortices, but there were no cerebrospinal fluid abnormalities. She achieved remission with anti-epileptic drugs alone. However, encephalitis recurred four months later when pleocytosis appeared, and steroid therapy was effective. Altogether, EPC without typical cerebrospinal fluid features can be an early sign of anti-MOG antibody-positive encephalitis. Thus, patients with EPC of unknown etiology need to be screened for anti-MOG antibodies.

Partial duplication of DHH causes minifascicular neuropathy: A novel mutation detection of DHH

Minifascicular neuropathy (MN) is an extremely rare developmental malformation in which peripheral nerves are composed of many small fascicles. Only one patient with MN with 46XY gonadal dysgenesis (GD) was found to carry a mutation affecting the start codon in desert hedgehog (DHH). We identified an identical novel rearrangement mutation of DHH in two consanguineous families with MN, confirming mutations in DHH cause MN with 46XY GD. The patients with the 46XY karyotype developed GD, whereas a patient with the 46XX karyotype did not. These findings further support that DHH has important roles in perineural formation and male gonadal differentiation.

Atypical parkinsonism caused by Pro105Leu mutation of prion protein: A broad clinical spectrum

Objective:

To delineate molecular and clinical characteristics of 3 families with PRNP P105L mutation, a variant of Gerstmann-Sträussler-Scheinker syndrome whose main motor symptoms were parkinsonism and/or involuntary movements.

Methods:

The causative mutation was first determined in the affected patients of family 1 using whole-exome sequencing, and then mutational analysis was extended to families 2 and 3. The clinical features of the patients of these 3 families were summarized. Haplotype analysis was performed using high-density single nucleotide polymorphism array.

Results:

The whole-exome sequencing revealed that the heterozygous mutation c.314C>T (p.P105L) in PRNP was the only known pathogenic mutation shared by the 3 patients of the family with autosomal dominant parkinsonism. We further identified the same mutation in patients of the other 2 families with autosomal dominant parkinsonism and/or involuntary movements. The clinical features of our patients with PRNP P105L mutation included various motor symptoms such as parkinsonism and involuntary movements in addition to progressive dementia. The clinical features in part overlapped with those of other forms of inherited prion diseases, such as fatal familial insomnia and Huntington disease-like type 1. The patients with PRNP P105L mutation shared a haplotype spanning 7.1 Mb around PRNP, raising the possibility that the mutations in the patients originated from a common founder.

Conclusion:

Most of the patients presented with parkinsonism in addition to progressive dementia. Although spastic paraparesis has been emphasized as the main clinical feature, the clinical spectrum of patients with PRNP P105L is broader than expected.

Performance of indirect immunofluorescence assay, immunochromatography assay and reverse transcription-polymerase chain reaction for detecting human respiratory syncytial virus in nasopharyngeal aspirate samples

Comparison of the use of indirect immunofluorescence assay (IFA), immunochromatography assay (ICA-BD) and reverse transcription-polymerase chain reaction (RT-PCR) for detecting human respiratory syncytial virus (HRSV) in 306 nasopharyngeal aspirates samples (NPA) was performed in order to assess their analytical performance. By comparing the results obtained using ICA-BD with those using IFA, we found relative indices of 85.0% for sensitivity and 91.2% for specificity, and the positive (PPV) and negative (NPV) predictive values were 85.0% and 91.2%, respectively. The relative indices for sensitivity and specificity as well as the PPV and NPV for RT-PCR were 98.0%, 89.0%, 84.0% and 99.0%, respectively, when compared to the results of IFA. In addition, comparison of the results of ICA-BD and those of RT-PCR yielded relative indices of 79.5% for sensitivity and 95.4% for specificity, as well as PPV and NPV of 92.9% and 86.0%, respectively. Although RT-PCR has shown the best performance, the substantial agreement between the ICA-BD and IFA results suggests that ICA-BD, also in addition to being a rapid and facile assay, could be suitable as an alternative diagnostic screening for HRSV infection in children.

Recombinant antigen-based immuno-slot blot method for serodiagnosis of syphilis

Three recombinant antigens of Treponema pallidum Nichols strain were fused with GST, cloned and expressed in Escherichia coli, resulting in high levels of GST-rTp47 and GST-rTp17 expression, and supplementation with arginine tRNA for the AGR codon was needed to obtain GST-rTp15 overexpression. Purified fusion protein yields were 1.9, 1.7 and 5.3 mg/l of cell culture for GST-rTp47, GST-rTp17 and GST-rTp15, respectively. The identities of the antigens obtained were confirmed by automated DNA sequencing using ABI Prism 310 and peptide mapping by Finningan LC/MS. These recombinant antigens were evaluated by immuno-slot blot techniques applied to 137 serum samples from patients with a clinical and laboratory diagnosis of syphilis (61 samples), from healthy blood donors (50 samples), individuals with sexually transmitted disease other than syphilis (3 samples), and from individuals with other spirochetal diseases such as Lyme disease (20 samples) and leptospirosis (3 samples). The assay had sensitivity of 95.1% (95% CI, 86.1 to 98.7%) and a specificity of 94.7% (95% CI, 87.0 to 98.7%); a stronger reactivity was observed with fraction rTp17. The immunoreactivity results showed that fusion recombinant antigens based-immuno-slot blot techniques are suitable for use in diagnostic assays for syphilis.

Analysis of Treponema pallidum recombinant antigens for diagnosis of syphilis by western blotting technique

Three GST fusion recombinant antigen of Treponema pallidum, described as GST-rTp47, GST-rTp17 and GST-rTp15 were analyzed by Western blotting techniques. We have tested 53 serum samples: 25 from patients at different clinical stages of syphilis, all of them presenting anti-treponemal antibody, 25 from healthy blood donors and three from patients with sexually transmitted disease (STD) other than syphilis. Almost all samples from patients with syphilis presented a strong reactivity with GST-rTp17 antigen. Some samples were non-reactive or showed a weak reaction with GST-rTp47 and/or GST-rTp15, and apparently there was no correlation with the stage of disease. There was no seropositivity among blood donors. No sample reacted with purified GST. We concluded that due to their specificity these recombinant antigens can be used as GST fusion protein for development of syphilis diagnostic assays.