Osteopathia striata with cranial sclerosis is a rare X-linked disorder. It is often lethal in male patients, and is considered X-linked dominant since affected females exhibit clinical signs, although milder than males. We describe here an adult male patient, with clinical and radiological signs similar to those described in female patients. Diagnosis was confirmed by the identification of an AMER1 mutation. The presence of long bones striation and the clinical phenotype of the patient also led to the diagnosis of non-mosaic Klinefelter syndrome, probably explaining the non-lethal and even rather minor phenotype compared to the rare affected males already described.