Ehlers-Danlos syndrome type VII: Clinical features and molecular defects

We evaluated the clinical features, molecular defects, and problems associa ted with the management of two patients who had type-VII Ehlers-Danlos synd rome and reviewed the cases of eighteen patients with this condition who ha d been reported on previously, The typical clinical features associated wit h this syndrome include bilateral congenital dislocation of the hip; severe generalized hypermobility of the joints; multiple dislocations of joints o ther than the hip; muscular hypotonia; and hyperelasticity, fragility, and a doughy texture of the skin. Collagen and DNA analyses demonstrated that both of our patients had type-V IIB Ehlers-Danlos syndrome, which is caused by heterozygous new mutations o f the COL1A2 gene that encodes the pro alpha 2(I) chain of type-I procollag en. The obligatory GT dinucleotide at the splice donor site of intron 6 was altered in both of our patients: one patient (Case 1) had an A substitutio n of the G nucleotide, and the other patient (Case 2) had a C substitution of the T nucleotide, Abnormal splicing resulted in the loss of the exon 6-e ncoded N-telopeptide, which includes the N-proteinase cleavage site. Despite multiple operative procedures, one of our patients, who was thirty- seven years old at the time of the most recent follow-up, continued to have persistent subluxation of the right hip and osteoarthritis of the left hip . Closed reduction of the dislocated hips, regardless of the type of immobi lization used, was unsuccessful in all twenty patients. The results of open reduction were improved when capsulorrhaphy was combined with iliac or fem oral osteotomy, or both.