Successful low-risk hematopoietic cell therapy in a mouse model of type 1 Gaucher disease.

Hematopoietic stem cell (HSC) based gene therapy offers the possibility of permanent correction for genetic disorders of the hematopoietic system. However, optimization of present protocols is required before gene therapy can be safely applied as general treatment of genetic diseases. In this study we have used a mouse model of type 1 Gaucher disease (GD) to demonstrate the feasibility of a low-risk conditioning regimen instead of standard radiation, which is associated with severe adverse effects. We first wanted to establish what level of engraftment and glucosylceramidase (GCase) activity is required to correct the pathology of the type 1 GD mouse. Our results demonstrate that a median WT cell engraftment of 7 % corresponding to GCase activity levels above 10 nmol/hr and mg protein was sufficient to reverse pathology within bone marrow (BM) and spleen in the GD mouse. Moreover, we applied non-myeloablative doses of busulphan as a pretransplant conditioning regimen and show that even WT cell engraftment in the range of 1-10% can confer a beneficial therapeutical outcome in this disease model. Taken together, our data provide encouraging evidence for the possibility to develop safe and efficient conditioning protocols for diseases that only require a low level of normal or gene corrected cells for a permanent and beneficial therapeutic outcome. ______________________________________________________________________________ Author contributions: I.B.E.: Conception and design, collection and assembly of data, data analysis and interpretation, manuscript writing; E.N.: Collection of data, data analysis and interpretation; J.-E.M.: Collection and assembly of data, data analysis and interpretation; M.E.: Collection and assembly of data, data analysis and interpretation; J.R.: Data analysis and interpretation, manuscript writing; S.K.: Conception and design, financial support, data analysis and interpretation, manuscript writing, final approval of manuscript

The risk of cholesteatoma in individuals with first-degree relatives surgically treated for the disease

IMPORTANCE:  Cholesteatoma in the middle ear is not regarded as a hereditary disease, but case reports of familial clustering exist in the literature, as well as observed familial cases in the clinical work. However, the knowledge regarding cholesteatoma as a hereditary disease is lacking in the literature. OBJECTIVE To assess the risk of cholesteatoma in individuals with a first-degree relative surgically treated for the same disease. DESIGN, SETTING, AND PARTICIPANTS: In this nested case-control study in the Swedish population between 1987 and 2018 of first-time cholesteatoma surgery identified from the Swedish National Patient Register, 2 controls per case were randomly selected from the population register through incidence density sampling, and all first-degree relatives for cases and controls were identified. Data were received in April 2022, and analyses were conducted between April and September 2022. EXPOSURE: Cholesteatoma surgery in a first-degree relative. MAIN OUTCOMES AND MEASURES: The main outcome was first-time cholesteatoma surgery. The association between having a first-degree relative with cholesteatoma and the risk of cholesteatoma surgery in the index persons was estimated by odds ratios (ORs) and 95% CIs through conditional logistic regression analysis. RESULTS: Between 1987 and 2018, 10 618 individuals with a first-time cholesteatoma surgery (mean [SD] age at surgery, 35.6 [21.5] years; 6302 [59.4%] men) were identified in the Swedish National Patient Register. The risk of having a cholesteatoma surgery was almost 4 times higher in individuals having a first-degree relative surgically treated for the disease (OR, 3.9; 95% CI, 3.1-4.8), but few cases were exposed overall. Among the 10 105 cases with at least 1 control included in the main analysis, 227 (2.2%) had at least 1 first-degree relative treated for cholesteatoma, while the corresponding numbers for controls were 118 of 19 553 control patients (0.6%). The association was stronger for individuals under the age of 20 years at first surgery (OR, 5.2; 95% CI, 3.6-7.6) and for a surgery involving the atticus and/or mastoid region (OR, 4.8; 95% CI, 3.4-6.2). There was no difference in the prevalence of having a partner with cholesteatoma between cases and controls (10 cases [0.3%] and 16 controls [0.3%]; OR, 0.92; 95% CI, 0.41-2.05), which implies that increased awareness does not explain the association. CONCLUSIONS AND RELEVANCE:  In this Swedish case-control study using nationwide register data with high coverage and completeness, the findings suggest that the risk of cholesteatoma in the middle ear is strongly associated with a family history of the condition. Family history was nevertheless quite rare and can therefore only explain a limited number of all cases; these families could be an important source for information regarding the genetic background for cholesteatoma disease