Abstract
Access to genetic testing and counselling in remote areas such as the Madeira archipelago, in the Northern Atlantic Ocean, may be complex. Different counselling methods, including telegenetics, should be explored. In this study, we characterise the Hereditary Breast/Ovarian Cancer (HBOC) families with Madeira ancestry enrolled in our programme. Of a total of 3,566 index patients tested between January 2000 and June 2018, 68 had Madeira ancestry and 22 were diagnosed with a pathogenic germline variant (PV). As in the whole group, BRCA2 PV were more frequent in Madeira patients (68.4%: c.9382C>T (26.3%), c.658_659del (21%), c.156_157insAlu (10.5%), c.793+1G>A (5.3%) and c.298A>T (5.3%). However, the most frequently diagnosed PV in Madeira patients was the BRCA1 c.3331_3334del (31.6%). BRCA1/2 detection rates were 27.9% and 10.5% for Madeira and the whole group, respectively. This study is the first characterisation of HBOC patients with Madeira ancestry. A distinct pattern of BRCA1/2 variants was observed, and the geographic clustering of BRCA1 c.3331_3334del variant may support the possibility of a founder mutation previously described in Northern Portugal. The high detection rate observed reinforces the need to reduce gaps in access to genetic testing in Madeira and other remote areas. According to current guidelines, timely identification of HBOC patients can contribute to their ongoing care and treatment.
Highlights
The identification of pathogenic BRCA1 and BRCA2 variants has had a marked impact on cancer prevention and therapy, with criteria for BRCA1/2 testing being included in several cancer treatment and prevention guidelines [1,2,3]
We reviewed all consecutive Hereditary Breast/Ovarian Cancer (HBOC) families with Madeira ancestry registered in our programme, explored their BRCA1/2 genotyping results and compared them with our data from continental Portugal
Genetic testing was proposed for patients with a combined probability of at least 10% of having a BRCA1/2 pathogenic variant (PV), but the criteria for testing have been expanded over time, including patients without a family history of cancer [13]
Summary
The identification of pathogenic BRCA1 and BRCA2 variants has had a marked impact on cancer prevention and therapy, with criteria for BRCA1/2 testing being included in several cancer treatment and prevention guidelines [1,2,3]. The expansion of recommendations for BRCA1/2 testing has challenged established delivery models of care for access to genetic counselling and testing [1, 4]. Several models, including telegenetics, have been proposed to improve access to genetic testing without compromising quality of care [5]. These methods have not been found to be associated with long-term negative psychosocial outcomes [6]
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