Gain-of-function missense mutations of voltage-gated sodium channel Na(V)1.7 have been linked to the painful disorder inherited erythromelalgia. These mutations hyperpolarize activation, slow deactivation and enhance currents evoked by slow ramp stimuli (ramp currents). A correlation has recently been suggested between the age of onset of inherited erythromelalgia and the extent of hyperpolarizing shifts in mutant Na(V)1.7 channel activation; mutations causing large activation shifts have been linked to early age of onset inherited erythromelalgia, while mutations causing small activation shifts have been linked to age of onset within the second decade of life. Here, we report a family with inherited erythromelalgia with an in-frame deletion of a single residue--leucine 955 (Del-L955) in DII/S6. The proband did not show symptoms until the age of 15 years, and her affected mother only experienced mild symptoms during adolescence, which disappeared at the age of 38 years. Del-L955 shows no effect on Na(V)1.7 current density and fast inactivation, but causes an approximately -24 mV shift in activation, together with increases in amplitude of persistent currents and ramp currents. The mutation also produces an approximately -40 mV shift in slow inactivation, which reduces channel availability. Comparison of the effects of the Del-L955 mutation on dorsal root ganglion neuron hyperexcitability with those produced by another inherited erythromelalgia mutation (L858F) that does not enhance slow inactivation suggests that a delayed age of onset and milder symptoms in association with a large shift of channel activation, enhanced persistent and enhanced ramp currents may be related to the approximately -40 mV shift in slow inactivation for Del-L955, the largest shift thus far demonstrated in mutant Na(V)1.7 channels. Our results suggest that despite the pivotal role of activation shift in inherited erythromelalgia development, slow inactivation may regulate clinical phenotype by altering channel availability.

This study expands the spectrum of heritable pain disorders linked to gain-of-function mutations in Na1.9, strengthening human validation of this channel as a potential therapeutic target for pain.

Summary The droplet digital polymerase chain reaction (ddPCR) is a novel molecular technique that allows rapid quantification of rare target DNA sequences. Aim of this study was to explore the feasibility of the ddPCR technique to detect pathogen DNA in whole blood and to assess the diagnostic accuracy of ddPCR to detect bloodstream infections (BSIs), benchmarked against blood cultures. Broad‐range primers and probes were designed to detect bacterial 16S rRNA (and Gram stain for differentiation) and fungal 28S rRNA. To determine the detection limit of ddPCR, 10‐fold serial dilutions of E. coli and C. albicans were spiked in both PBS and whole blood. The diagnostic accuracy of ddPCR was tested in historically collected frozen blood samples from adult patients suspected of a BSI and compared with blood cultures. Analyses were independently performed by two research analysts. Outcomes included sensitivity and specificity of ddPCR. Within 4 h, blood samples were drawn, and DNA was isolated and analysed. The ddPCR detection limit was approximately 1–2 bacteria or fungi per ddPCR reaction. In total, 45 blood samples were collected from patients, of which 15 (33%) presented with positive blood cultures. The overall sensitivity of ddPCR was 80% (95% CI 52–96) and specificity 87% (95% CI 69–96). In conclusion, the ddPCR technique has considerable potential and is able to detect very low amounts of pathogen DNA in whole blood within 4 h. Currently, ddPCR has a reasonable sensitivity and specificity, but requires further optimization to make it more useful for clinical practice.

BackgroundAlpha-1 antitrypsin (A1AT) deficiency, caused by the Z allele (p.E342K) and S allele (p.E264V) in the SERPINA1 gene, can induce liver and pulmonary disease. Different mechanisms appear to be responsible for the pathogenesis of these divergent disease expressions. The c.-1973T >C polymorphism located in the SERPINA1 promoter region is found more frequent in A1AT deficiency patients with liver disease compared to patients with pulmonary disease, but data are lacking regarding contribution to the development of liver diseases caused by other aetiologies.AimTo study the prevalence of c.-1973T >C, Z allele and S allele in a cohort of patients with liver disease of various aetiologies compared with healthy controls and to evaluate its effect on disease progression.MethodsA total of 297 patients with liver disease from various aetiologies and 297 age and gender matched healthy controls were included. The c.-1973T >C polymorphism and Z and S alleles of the SERPINA1 gene were analyzed by real-time PCR.Resultsc.-1973T >C was similarly distributed between patients with liver disease of various origins and healthy controls. Furthermore, the distribution of c.-1973T >C was independent from aetiology subgroup. In patients with liver disease mean ages at of onset of liver disease were 44.4, 42.3 and 40.7 years for the c.-1973 T/T, T/C and C/C genotype respectively (NS). S allele heterozygosity was increased in patients with drug induced liver injury (DILI), (OR 4.3; 95%CI 1.1-17.2).ConclusionIn our study, c.-1973T >C polymorphism was not a risk factor for liver disease of various aetiologies. In addition, S allele heterozygosity might contribute to the development of DILI.

ObjectivesWe tested whether complementary use of the somatostatin analogue pasireotide would augment efficacy of aspiration sclerotherapy of hepatic cysts.MethodsWe conducted a double-blind, placebo-controlled trial in patients who underwent aspiration sclerotherapy of a large (>5 cm) symptomatic hepatic cyst. Patients were randomized to either intramuscular injections of pasireotide 60 mg long-acting release (n = 17) or placebo (sodium chloride 0.9 %, n = 17). Injections were administered 2 weeks before and 2 weeks after aspiration sclerotherapy. The primary endpoint was proportional cyst diameter reduction (%) from baseline to 6 weeks. Secondary outcomes included long-term cyst reduction at 26 weeks, patient-reported outcomes including the polycystic liver disease-questionnaire (PLD-Q) and safety.ResultsThirty-four patients (32 females; 53.6 ± 7.8 years) were randomized between pasireotide or placebo. Pasireotide did not improve efficacy of aspiration sclerotherapy at 6 weeks compared to controls (23.6 % [IQR 12.6–30.0] vs. 21.8 % [9.6–31.8]; p = 0.96). Long-term cyst diameter reduction was similar in both groups (49.1 % [27.0–73.6] and 45.6 % [29.6–59.6]; p = 0.90). Mean PLD-Q scores improved significantly in both groups (p < 0.01) without differences between arms (p = 0.92).ConclusionsIn patients with large symptomatic hepatic cysts, complementary pasireotide to aspiration sclerotherapy did not improve cyst reduction or clinical response.Key Points• Complementary pasireotide treatment does not improve efficacy of aspiration sclerotherapy.• Cyst fluid reaccumulation after aspiration sclerotherapy is a transient phenomenon.• Aspiration sclerotherapy strongly reduces symptoms and normalizes quality of life.Electronic supplementary materialThe online version of this article (10.1007/s00330-017-5205-1) contains supplementary material, which is available to authorized users.