Heartbeat: The potential power of genotype-phenotype correlations (Heart)

We now easily can do genetic testing for specific inherited conditions in our patients; indeed, sequencing of the whole genome is possible. Yet, even with inherited conditions due to changes in a single gene, such as the FBN1 gene in Marfan syndrome, there is considerable variation in the specific mutation in each patient. Presumably, resultant differences in the abnormal fibrillin-1 protein translate into differences in clinical disease manifestations. A better understanding of the genotype–phenotype relationships in Marfan syndrome might be useful in identifying which patients require more frequent diagnostic evaluation or earlier intervention to prevent adverse consequences of the underlying inherited condition. In this issue of Heart, Franken and colleagues1 classified FBN1 mutations in 290 Marfan patients as either ‘dominant-negative’ (61%) if the mutated and non-mutated fibrillin-1 proteins both were incorporated into the extracellular matrix or as ‘haplo-insufficient’ (39%) if there was a decreased total amount of fibrillin-1...