Family genetic screening in rare hereditary diseases

Abstract

Family genetic testing of probands with newly diagnosed rare hereditary diseases including Fabry disease improves early diagnosis and allows to initiate specific treatment, if available, at earlier stage in affected family members. Diagnosis of Fabry disease, an X-linked lysosomal storage disorder affecting kidneys, heart, brain and other organs, is usually late due to low awareness of physicians about rare diseases. Moreover, early symptoms can be non-specific (e.g. gastrointestinal disorders and autonomic neuropathy) or misleading (e.g. recurrent unexplained fever) whereas characteristic skin rash and keratopathy (cornea verticillata) are frequently overlooked. Undiagnosed patients with Fabry disease can be detected by screening in at-risk populations, such as patients with end-stage renal disease undergoing dialysis or renal transplantation, patients with unexplained left ventricular hypertrophy, and young adults with a history of stroke or transient ischemic attack who have a higher prevalence of the disease compared to general population. High-risk screening paves the way to family screening to identify affected relatives, including children, who can benefit from earlier treatment and genetic counselling. The major barriers to family screening include costs of testing, cultural and societal issues, stigma associated with a diagnosis of genetic disease, low contacts in the family, weak infrastructure, national regulations.