[Double malformation discovered during investigations for hypertension; single pelvic kidney and occipitovertebral joint malformation (author's transl)].

A young Portuges eman with a spastic gait was found to have a kidney lying below the bladder. This was the only kidney present and its blood supply was derived from a renal artery which was also the only one present. This renal abnormality was associated with a major malformation of the occipitovertebral joint (occipitalization of the atlas, total occipito-atlanto-odontoid dissociation above the line of the digastric). The possible relationship between these two affections is discussed.