To date, neuromyotonia in the context of an inherited axonal neuropathy has been linked to autosomal recessive mutations in the histidine triad nucleotide binding protein 1 (HINT1) gene. In this study we describe two unrelated male patients with late-onset, predominantly motor, axonal neuropathy with neuromyotonia, who carried an autosomal dominant c.103G > A mutation in the myelin protein zero (MPZ) gene (NM_000530.8:c.103G > A, p.Asp35Asn), identified by whole-exome sequence analysis (WES).  CASE DESCRIPTIONS: The first patient presented progressive leg muscle weakness and stiffness with difficulty in walking, pain and increased creatine kinase levels,during his fifth decade of life. Electrophysiological examination revealed findings of an axonal, length-dependent polyneuropathy with spontaneous activity, mainly neuromyotonia. Over the 20-year disease course since the first reported symptoms, muscle weakness gradually worsened and he is currently unable to walk without assistance. A second male patient, unrelated to the first one, showed similar clinical and electrophysiological features of a length-dependent axonal neuropathy with neuromyotonia. WES detected the same MPZ missensevariant.  CONCLUSION: This study suggests a novel entity in the spectrum of Charcot-Marie-Tooth hereditary neuropathies, characterized by autosomal dominant axonal neuropathy with neuromyotonia (AD-NMAN).

This study aimed to understand long-term coping responses of mothers (N = 287) receiving genetic counseling and testing (GCT) for hereditary breast/ovarian cancer (HBOC) syndrome. Psychological characteristics, including cancer-specific distress (Impact of Events Scale-Revised, α = .85) and coping (Brief COPE, α = .93) were assessed via structured personal communication, along with epidemiologic items assessing personal and family history of cancer. Genetic risk was determined by BRCA1/2 carriage. A principal component analysis was conducted on the coping measure to reduce its summary score to active coping (α = .91) with nine approach-oriented strategies responsive to stress. A multivariable regression model examined the main and interacting effects of clinical and psychological characteristics on maternal coping. Personal cancer history (F = 4.99, df = 1, p = .026), BRCA test result (F = 22.20, df = 1, p < .001), and cancer-specific distress (F = 17.80, df = 1, p < .001) were associated with greater engagement in active coping strategies. When controlling for cancer-specific distress, the interaction between personal cancer history and genetic test results was significant, such that women previously unaffected by cancer who received positive BRCA results reported the greatest levels of active coping (F = 7.92, p < .001). These findings indicate that previous cancer history, genetic risk, and psychological distress independently and jointly impact how women adapt to the threat of cancer over time.

When a pathogenic BRCA1 or BRCA2 mutation is identified in a family, cascade genetic testing of family members is recommended since the results may inform screening or treatment decisions in men and women. However, rates of cascade testing are low, and men are considerably less likely than women to pursue cascade testing. To facilitate cascade testing in men, we designed a Web-based genetic education tool that addressed barriers to cascade testing, was individually tailored, delivered proactively, and could be used in lieu of pretest genetic counseling to streamline the cascade testing process. We randomized 63 untested men from hereditary cancer families to Web-based genetic education (WGE) versus enhanced usual care (EUC). WGE participants were provided access to a genetic education website after which they could accept or decline genetic testing or opt for pretest genetic counseling. EUC participants received an informational brochure and a letter informing them of their eligibility for genetic testing and recommending they schedule genetic counseling. The primary outcome was the uptake of genetic testing. Men in the WGE group were more likely to complete genetic counseling and/or genetic testing (43% vs. 12.1%; χ2 [n = 63, df = 1] = 7.77, p = 0.005). WGE participants were also more likely to complete genetic testing compared to men in the EUC group (30% vs. 9.1%; χ2 [n = 63, df = 1] = 4.46, p = 0.03). This preliminary trial suggests that a streamlined approach to genetic testing using proactively delivered genetic education may reduce barriers to cascade testing for at-risk men, leading to increased uptake. These results should be interpreted cautiously given the select sample and high rate of non-response.

Pathogenic germline variants in the mismatch repair (MMR) genes are associated with an increased risk of prostate cancer (PCa). Since 2010 we have recommended MMR carriers annual PSA testing from the age of 40. Prospective studies of the outcome of long-term PSA screening are lacking. This study aimed to investigate the incidence and characteristics of PCa in Norwegian MMR carriers attending annual PSA screening (PSA threshold >3.0 ng/mL) to evaluate whether our recommendations should be continued. This is a prospective observational study of 225 male MMR carriers who were recommended annual PSA screening by the Section of Inherited Cancer, Oslo University Hospital from 2010 and onwards. Incidence and tumor characteristics (age, PSA at diagnosis, Gleason score, TNM score) were described. IHC and MSI-analyses were done on available tumors. Standardized incidence ratio (SIR) was calculated based on data from the Cancer Registry of Norway. Twenty-two of 225 (9.8%) had been diagnosed with PCa, including 10/69 (14.5%) MSH2 carriers and 8/61 (13.1%) MSH6 carriers. Ten of 20 (50%) tumors had Gleason score ≥4 + 3 on biopsy and 6/11 (54.5%) had a pathological T3a/b stage. Eight of 17 (47.1%) tumors showed abnormal staining on IHC and 3/13 (23.1%) were MSI-high. SIR was 9.54 (95% CI 5.98-14.45) for all MMR genes, 13.0 (95% CI 6.23-23.9) for MSH2 and 13.74 for MSH6 (95% CI 5.93-27.08). Our results indicate that the MMR genes, and especially MSH2 and MSH6, are associated with a significant risk of PCa, and a high number of tumors show aggressive characteristics. While the impact of screening on patient outcomes remains to be more firmly established, the high SIR values we observe provide support for continued PSA screening of MSH2 and MSH6 carriers. Studies are needed to provide optimal recommendations for PSA-threshold and to evaluate whether MLH1 and PMS2 carriers should not be recommended screening.

KCNJ10 and CAPN1 variants cause "spinocerebellar" ataxia in dogs, but their association with generalized myokymia and neuromyotonia remains unclear. To investigate the association between KCNJ10 and CAPN1 and myokymia or neuromyotonia, with or without concurrent spinocerebellar ataxia. Thirty-three client-owned dogs with spinocerebellar ataxia, myokymia neuromytonia, or a combination of these signs. Genetic analysis of a cohort of dogs clinically diagnosed with spinocerebellar ataxia, myokymia or neuromyotonia. KCNJ10 c.627C>G and CAPN1 c.344G>A variants and the coding sequence of KCNA1, KCNA2, KCNA6, KCNJ10 and HINT1 were sequenced using DNA extracted from blood samples. Twenty-four Jack Russell terriers, 1 Jack Russell terrier cross, 1 Dachshund and 1 mixed breed with spinocerebellar ataxia were biallelic (homozygous) for the KCNJ10 c.627C>G variant. Twenty-one of those dogs had myokymia, neuromyotonia, or both. One Parson Russell terrier with spinocerebellar ataxia alone was biallelic for the CAPN1 c.344G>A variant. Neither variant was found in 1 Jack Russell terrier with ataxia alone, nor in 3 Jack Russell terriers and 1 Yorkshire terrier with myokymia and neuromyotonia alone. No other causal variants were found in the coding sequence of the investigated candidate genes in these latter 5 dogs. The KCNJ10 c.627C>G variant, or rarely the CAPN1 c.344G>A variant, was confirmed to be the causal variant of spinocerebellar ataxia. We also report the presence of the KCNJ10 c.627C>G variant in the Dachshund breed. In dogs with myokymia and neuromyotonia alone the reported gene variants were not found. Other genetic or immune-mediated causes should be investigated to explain the clinical signs of these cases.