Clinical, morphological, and biochemical phenotype of a new case of Ehlers-Danlos syndrome type VIIC

Abstract

Ehlers-Danlos syndrome (EDS) type VIIC is a newly recognized human disorder which results from failure to remove the amino-terminal propeptide of type I procollagen. Four cases of EDS type VIIC have been reported, and here we describe a fifth case. The propositus was a 1,445 g male infant born at 30 weeks of gestation following premature rupture of membranes. He had wide fontanelles, prominent eyes with swollen eyelids and blue sclerae, anteverted nostrils, micrognathia, umbilical hernia, short stubby fingers, and cutis laxa with hirsutism. At age 3 months, during the repair of the umbilical hernia, he was noted to have unusual skin fragility. Examination of skin by scanning electron microscopy showed frayed collagen fibrils, and transmission electron microscopy showed the hieroglyphic collagen fibril morphology characteristic of the disorder. As reported in other cases, cultured fibroblasts synthesized type I procollagen that was very poorly processed at the amino-terminal propeptide cleavage site. the 5 known cases of human EDS type VIIC characterize a distinct clinical phenotype, making this condition recognizable at birth before manifestation of severe skin fragility. The diagnosis can be confirmed by biochemical studies of type I procollagen synthesis and by electron microscopic examination of skin.