With the skin hyperextensibility, joint hypermobility, papyraceous scar revealed by physical examination, and the heterozygous pathogenic variant c1997G > A (p.P659P) in COL5A2 gene revealed by whole exome sequencing, the diagnosis of the classical Ehlers-Danlos syndrome was made.
Results thus suggest that COL5A2(+/-) humans, although unlikely to present with frank classic Ehlers-Danlos syndrome, are likely to have fragile connective tissues with increased susceptibility to trauma and certain chronic pathologic conditions.
Col5a2, a gene previously not specifically linked to MI response but responsible for the classic type of Ehlers-Danlos syndrome, was found to have many and strong co-expression associations within this community (11 connections with ρ > 0.85).
However, because no prospective molecular studies of COL5A1 and COL5A2 have been performed in a clinically well-defined patient group, this number may underestimate the real proportion of patients with classic Ehlers-Danlos syndrome harboring a mutation in one of these genes.
Mutations in COL5A1 and COL5A2, encoding the type V collagen proalpha1- and proalpha2-chain, are found in approximately 50% of patients with classic EDS.
Seven patients with classic Ehlers-Danlos syndrome (EDS) due to COL5A1 haploinsufficiency and one with an exon-skipping mutation in COL5A2 underwent an ocular examination, corneal topography, pachymetry, and specular microscopy.
Mutations in the COL5A1 and the COL5A2 gene encoding the alpha1(V) and the alpha2(V) chains, respectively, of type V collagen have been shown to cause the disorder, but it is unknown what proportion of classic EDS patients carries a mutation in these genes.
However, linkage studies in other EDS I families indicate the disorder is heterogeneous; linkage to both COL5A1 and COL5A2 was excluded in two other families with EDS I while a fourth family was concordant for linkage to COL5A1 (Z = 2.11; theta = 0.00).