Metaphyseal enchondrodysplasia with 2-hydroxy-glutaric aciduria: Observation of a third case and further delineation

In the course of evaluating a 17 months old boy with waddling gait and swollen joints, we found generalized, severe ossification defects in the metaphyses of his long bones. The differential diagnosis included nutritional or genetic rickets, metaphyseal dysplasia, and enchondrodysplasia. Calcium, phosphate and alkaline phosphatase were normal, while targeted analysis of urinary organic acids repeatedly revealed excretion of 2-hydroxy-glutaric acid. Thus, this child appears to have an unusual combination of findings described in just two other patients so far, a girl and a boy, and called 'spondyloenchondrodysplasia with D-2-hydroxy-glutaric aciduria'. These three cases are similar in terms of severe metaphyseal lesions, mild vertebral involvement, and presence of 2-hydroxy-glutaric acid in the urine. We consider this a radiographically and biochemically distinct entity, for which we suggest the name of 'metaphyseal enchondrodysplasia with 2-hydroxy-glutaric aciduria'.