Identification of a novel heterozygous DYSF variant in a large family with a dominantly-inherited dysferlinopathy.

AIMS: Dysferlinopathy is an autosomal recessive muscular dystrophy, caused by bi-allelic variants in the gene encoding dysferlin (DYSF). Onset typically occurs in the second to third decade and is characterised by slowly progressive skeletal muscle weakness and atrophy of the proximal and/or distal muscles of the four limbs. There are rare cases of symptomatic DYSF variant carriers. Here, we report a large family with a dominantly inherited hyperCKaemia and late-onset muscular dystrophy. METHODS AND RESULTS: Genetic analysis identified a co-segregating novel DYSF variant [NM_003494.4:c.6207del p.(Tyr2070Metfs*4)]. No secondary variants in DYSF or other dystrophy-related genes were identified on whole genome sequencing and analysis of the proband's DNA. Skeletal muscle involvement was milder and later onset than typical dysferlinopathy presentations; these clinical signs manifested in four individuals, all between the fourth and sixth decades of life. All individuals heterozygous for the c.6207del variant had hyperCKaemia. Histological analysis of skeletal muscle biopsies across three generations showed clear dystrophic signs, including inflammatory infiltrates, regenerating myofibres, increased variability in myofibre size and internal nuclei. Muscle magnetic resonance imaging revealed fatty replacement of muscle in two individuals. Western blot and immunohistochemical analysis of muscle biopsy demonstrated consistent reduction of dysferlin staining. Allele-specific quantitative PCR analysis of DYSF mRNA from patient muscle found that the variant, localised to the extreme C-terminus of dysferlin, does not activate post-transcriptional mRNA decay. CONCLUSIONS: We propose that this inheritance pattern may be underappreciated and that other late-onset muscular dystrophy cases with mono-allelic DYSF variants, particularly C-terminal premature truncation variants, may represent dominant forms of disease.

Targeted gene panel use in 2249 neuromuscular patients: the Australasian referral center experience.

OBJECTIVE: To develop, test, and iterate a comprehensive neuromuscular targeted gene panel in a national referral center. METHODS: We designed two iterations of a comprehensive targeted gene panel for neuromuscular disorders. Version 1 included 336 genes, which was increased to 464 genes in Version 2. Both panels used TargetSeqTM probe-based hybridization for target enrichment followed by Ion Torrent sequencing. Targeted high-coverage sequencing and analysis was performed on 2249 neurology patients from Australia and New Zealand (1054 Version 1, 1195 Version 2) from 2012 to 2015. No selection criteria were used other than referral from a suitable medical specialist (e.g., neurologist or clinical geneticist). Patients were classified into 15 clinical categories based on the clinical diagnosis from the referring clinician. RESULTS: Six hundred and sixty-five patients received a genetic diagnosis (30%). Diagnosed patients were significantly younger that undiagnosed patients (26.4 and 32.5 years, respectively; P = 4.6326E-9). The diagnostic success varied markedly between disease categories. Pathogenic variants in 10 genes explained 38% of the disease burden. Unexpected phenotypic expansions were discovered in multiple cases. Triage of unsolved cases for research exome testing led to the discovery of six new disease genes. INTERPRETATION: A comprehensive targeted diagnostic panel was an effective method for neuromuscular disease diagnosis within the context of an Australasian referral center. Use of smaller disease-specific panels would have precluded diagnosis in many patients and increased cost. Analysis through a centralized laboratory facilitated detection of recurrent, but under-recognized pathogenic variants.

The Effect of Adjacent Materials on the Propagation of Phonon Polaritons in Hexagonal Boron Nitride.

In order to apply the ability of hexagonal boron nitride (hBN) to confine energy in the form of hyperbolic phonon polariton (HPhP) modes in photonic-electronic devices, approaches to finely control and leverage the sensitivity of these propagating waves must be investigated. Here, we show that by surrounding hBN with materials of lower/higher dielectric responses, such as air and silicon, lower/higher surface momenta of HPhPs can be achieved. Furthermore, an alternative method for preparing thin hBN crystals with minimum contamination is presented, which provides opportunities to study the sensitivity of the damping mechanism of HPhPs on adsorbed materials. Infrared scanning near-field optical microscopy (IR-SNOM) results suggest that the reflections at the upper and lower hBN interfaces are primary causes of the damping of HPhPs, and that the damping coefficients of propagating waves are highly sensitive to adjacent layers, suggesting opportunities for sensor applications.

Hexagonal Boron Nitride Self-Launches Hyperbolic Phonon Polaritons.

Hexagonal boron nitride (hBN) is a 2D material that supports traveling waves composed of material vibrations and light, and is attractive for nanoscale optical devices that function in the infrared. However, the only current method of launching these traveling waves requires the use of a metal nanostructure. Here, we show that the polaritonic waves can be launched into the 2D structure by folds within hBN, alone, taking advantage of the intrinsic material properties. Our findings suggest that structural continuity between the fold and hBN crystal is crucial for creating self-launched waves with a constant phase front. This approach offers a single material system to excite the polaritonic modes, and the approach is applicable to a broad range of 2D crystals and thus could be useful in future characterization.

HLA typing using bead-based methods.

The LABType(®) SSO (One Lambda, Inc) and Gen-Probe LIFECODES HLA-SSO HLA Typing tests are rapid and efficient assays for determining human leukocyte antigens (HLAs). The principle of these assays involves the hybridization of reverse sequence-specific oligonucleotide probes each attached to a unique colour coded microsphere to identify HLA class I and class II alleles. Target DNA is polymerase chain reaction (PCR) amplified using group-specific primers and then biotinylated which allows it to be detected using R-Phycoerythrin-conjugated Streptavidin. The PCR product is then denatured and allowed to hybridise to complementary DNA probes conjugated to fluorescently code microsperes. The Luminex(®) Flow Analyser achieves detection by determining the fluorescent intensity of PE on each microsphere. The assignment of HLA alleles is based on the reaction pattern of the various beads compared to patterns with known HLA alleles.