The patient was a man who died at the age 38 years. His family history was unremarkable. There was no abnormal developmental history. At the age of 26, the patient suffered a pathological fracture of the right tibia, and X-ray confirmed bone resorption in the right tibia. As for mental status, the patient tended to be euphoric. After that, bone resorption was also seen in other long bones. At the age of 33, the patient could not walk after

suffering a right femoral neck fracture. He was apathetic and exhibited behavioral abnormalities. At the age of 38, he could not move or speak and subsequently died. General pathological examination showed yellow opaque gelatinous substances in the medullary cavities, matching translucent cystic lesions in the femur, tibia, and fibula on X-rays. Light microscopy

showed numerous membranocystic changes in AZD1208 nmr the substances. The brain weighed 1050 g. Symmetric systemic cerebral atrophy, in particular atrophy of the cerebral white matter in the occipital and temporal lobes, was confirmed. Histological examination showed white matter degeneration and diffuse sclerosis accompanied by astroglial proliferation. Severe demyelination was confirmed. Axonal degeneration and destruction were marked. In demyelinated areas, fat granule cells appeared, and lipid granule-positive Tanespimycin cells aggregated around vessels. Cerebral cortical neurons were relatively maintained. In the brain, no membranocystic lesions could be recognized. In the DAP12 gene, the patient had a conversion of nucleotide at position 116 resulting in serine 38 to asparagine substitution. Nasu-Hakola disease (NHD) is very rare and was first reported separately by Nasu and Hakola around the same time in the 1970s. This autosomal recessive inherited disorder is characterized by progressive dementia and repeated pathological fractures during adolescence.1,2 In recent

years, studies 17-DMAG (Alvespimycin) HCl have demonstrated that NHD is caused by a mutation in the DAP12 gene (DNAX-activating protein 12) (TYROBP: TYRO protein tyrosine kinase binding protein, KARAP: killer-cell activating receptor associated protein) or the TREM2 gene (triggering receptor expressed on myeloid cells 2).3,4 The present paper demonstrates the first patient reported by Nasu and reviews NHD. There was no notable family history or consanguineous marriage, and the patient’s developmental history was not abnormal. At the age of 26 years, the patient suffered a pathological fracture in the right tibia. Due to poor bone fusion, the patient visited the Department of Orthopedic Surgery, Shinshu University Hospital, and X-ray examination confirmed bone resorption in the right tibia. Psychologically, the patient was talking quickly, loquacious, cheerful and euphoric. The next year, bone resorption was also seen in the lower end of the right tibia and fibula.