Ehlers-Danlos syndrome type VI in a 17-year-old Iranian boy with severe muscular weakness - a diagnostic challenge?

ABSTRACT

The Ehlers-Danlos syndrome type VI [EDSVI] is an autosomal recessive connective tissue disease which is characterized by severe hypotonia at birth, progressive kyphoscoliosis, skin hyperelasticity and fragility, joint hypermobility and [sub-]luxations, microcornea, rupture of arteries and the eye globe, and osteopenia. The enzyme collagen lysyl hydroxylase [LH1] is deficient in these patients due to mutations in the PLOD1 gene. We report a 17-year-old boy, born to related parents, with severe kyphoscoliosis, scar formation, joint hypermobility and multiple dislocations, muscular weakness, rupture of an ocular globe, and a history of severe infantile hypotonia. EDS VI was suspected clinically and confirmed by an elevated ratio of urinary total lysyl pyridinoline to hydroxylysyl pyridinoline, abnormal electrophoretic mobility of the alpha-collagen chains, and mutation analysis. Because of the high rate of consanguineous marriages in Iran and, as a consequence thereof, an increased rate of autosomal recessive disorders, we urge physicians to consider EDS VI in the differential diagnosis of severe infantile hypotonia and muscular weakness, a disorder which can easily be confirmed by the analysis of urinary pyridinolines that is highly specific, sensitive, robust, fast, non-invasive, and inexpensive