EssentialsThe population prevalence of hereditary thrombotic thrombocytopenic purpura (TTP) is unknown. We studied the prevalence of hereditary TTP and population frequencies of two ADAMTS-13 mutations. A high frequency of hereditary TTP related to ADAMTS-13 mutation c.4143_4144dupA was found. Vicinity of ABO blood group and ADAMTS-13 loci may facilitate screening of ADAMTS-13 mutations.Summary. Background: Hereditary thrombotic thrombocytopenic purpura (TTP) caused by ADAMTS-13 mutations is a rare, but serious condition. The prevalence is unknown, but it seems to be high in Norway. Objectives: To identify all patients with hereditary TTP in central Norway and to investigate the prevalence of hereditary TTP and the population frequencies of two common ADAMTS-13 mutations. Patients/Methods:Patients were identified in a cross-sectional study within the Central Norway Health Region by means of three different search strategies. Frequencies of ADAMTS-13 mutations, c.4143_4144dupA and c.3178 C>T (p.R1060W), were investigated in a populationbased cohort (500 alleles) and in healthy blood donors (2104 alleles) by taking advantage of the close neighborhood of the ADAMTS-13 and ABO blood group gene loci. The observed prevalence of hereditary TTP was compared with the rates of ADAMTS-13 mutation carriers in different geographical regions. Results: We identified 11 families with hereditary TTP in central Norway during the 10-year study period. The prevalence of hereditary TTP in central Norway was 16.7 9 10 À6 persons.The most prevalent mutation was c.4143_4144dupA, accounting for two-thirds of disease causing alleles among patients and having an allelic frequency of 0.33% in the central, 0.10% in the western, and 0.04% in the southeastern Norwegian population. The allelic frequency of c.3178 C>T (p.R1060W) in the population was even higher (0.3-1%), but this mutation was infrequent among patients, with no homozygous cases. Conclusions: We found a high prevalence of hereditary TTP in central Norway and an apparently different penetrance of ADAMTS-13 mutations.

Summary Population‐based studies from high‐quality nationwide cancer registries provide an important alternative to clinical trials in the assessment of the impact of modern myeloma treatment. Based on data from the Cancer Registry of Norway, we investigated trends in incidence and relative survival (RS) for 10 524 patients in three age groups diagnosed between 1982 and 2017. Nationwide myeloma drug consumption statistics were obtained from the Norwegian Institute of Public Health. Patients aged <65 years had a steady increase in both 5‐ and 10‐year RS across all calendar periods from 1982. For patients aged 65–79 years, RS was stable until the calendar period 1998–2002, followed by an improvement in both 5‐ and 10‐year RS. The 5‐year RS for patients aged ≥80 years also increased significantly between the first and the last calendar period. In conclusion, we demonstrate a significant improvement in 5‐year RS in all age groups. Improved RS in patients aged ≥80 years at the time of diagnosis is only rarely described in other population‐based studies. For patients aged ≥65 years, the improvement in RS coincides with the introduction of modern drugs, whereas patients aged <65 years had an ongoing improvement before the introduction of autologous stem‐cell transplant.

Objectives We conducted a population‐based study to assess the risk for multiple myeloma (MM) and other cancers in first‐ and second‐degree relatives of MM patients, and to investigate whether evidence of anticipation is present in familial MM. Methods We retrieved 24 845 first‐degree relatives and 41 008 second‐degree relatives of 7847 MM patients, and 86 984 first‐degree relatives, and 138 660 second‐degree relatives of 26 511 matched controls. A Cox model was used to assess the risk for MM and other cancers in relatives of MM patients. Anticipation was assessed by a Cox model, where all parents and offspring of MM patients were included in the risk set. Results In second‐degree relatives of MM patients, no overall significant association with an MM diagnosis was observed (HR 1.99; 95%CI:0.86–4.57). In parents and offspring of MM patients, we found no significant difference in the ages at onset of MM (HR 1.28;95% CI:0.50–3.28). In affected parent‐offspring pairs, we observed no statistically significant difference in overall survival between the generations (HR 0.74; 95%CI:0.20–2.69). Conclusions Overall, second‐degree relatives of MM patients were not associated with an increased risk for MM. Our study supports that genetic anticipation is not present in familial MM.