Scientific Background
The very rare, autosomal recessively inherited cardiac-valvular EDS (cvEDS) is characterized by severe heart valve involvement with mitral valve regurgitation, aortic valve regurgitation, atrial septal defect, ventricular dilatation, and ventricular hypertrophy, which usually requires mitral and aortic valve replacement. Other EDS-specific symptoms include variable skin hyperextensibility, atrophic scarring and generalized joint hypermobility.
To date, only eight patients from six families have been described, in whom homozygous or combined heterozygous variants in the COL1A2 gene have been identified. These are so-called null alleles, which lead to transcript instability, so that no pro-α2(I) collagen chains are detectable in collagen electrophoresis. In contrast to patients with osteogenesis imperfecta, there is no increased bone fragility in cvEDS.
References
Guarnieri et al. 2019, Am J Med Genet A 179:846 / Brady et al. 2017, Am J Med Genet C 175:70 / Malfait et al. 2006, J Med Genet 43:e36 / Schwarze et al. 2004, Am J Hum Genet 74:917 / Nicholls et al. 2001, J Med Genet 38:132