Case report 867. Membranous lipodystrophy (polycystic lipomembranous osteodysplasia)

Nasu-Hakola disease (PLOSL): report of five cases and review of the literature

The combination of bilateral lytic lesions in the bones of the lower and upper extremities and presenile dementia is characteristic of polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, also known as Nasu-Hakola disease. The clinical course of this rare and fatal disorder is characterized by pathologic fractures of these often painful lesions, rapid progression of dementia, and death in the fifth decade of life. The radiographic changes may be confused with cystic angiomatosis, focal metastasizing hemangioendothelioma, or Langerhans' cell histiocytosis. We report five patients to illustrate the clinical presentation, radiographic images, psychiatric abnormalities, and new genetic findings. Three of the patients were siblings. A biopsy is not needed to confirm the diagnosis of polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy because of the unique combination of radiographic and neurologic features.

Nasu-Hakola disease (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy--PLOSL): a dementia associated with bone cystic lesions. From clinical to genetic and molecular aspects

The authors review the clinical, radiological, electrophysiological, pathological, and molecular aspects of Nasu-Hakola disease (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy or PLOSL). Nasu-Hakola disease is a unique disease characterized by multiple bone cysts associated with a peculiar form of neurodegeneration that leads to dementia and precocious death usually during the fifth decade of life. The diagnosis can be established on the basis of clinical and radiological findings. Recently, molecular analysis of affected families revealed mutations in the DAP12 (TYROBP) or TREM2 genes, providing an interesting example how mutations in two different subunits of a multi-subunit receptor complex result in an identical human disease phenotype. The association of PLOSL with mutations in the DAP12 or TREM2 genes has led to improved diagnosis of affected individuals. Also, the possible roles of the DAP12/TREM2 signaling pathway in microglia and osteoclasts in humans are just beginning to be elucidated. Some aspects of this peculiar signaling pathway are discussed here.

Membranous lipodystrophy

Membranous lipodystrophy (ML) is a rare hereditary disorder of adipose tissue characterized by polycystic bone lesions and progressive dementia. We describe the case of a 36-year-old woman with mechanical bone pain. Routine laboratory analyses revealed only a type IV hyperlipoproteinemia and hyperexcretion of urinary calcium. Roentgenograms of short and long bones showed symmetrical, well-defined, non-expansile cystic lesions. Bone biopsy found a yellow lipid-like substance in the osteolytic lesions and histopathological studies were non-specific. Neuropsychiatric examination, including cranial computerized tomography (CT), was found to be normal. According to clinical, analytical, radiological and histological findings ML was the diagnosis. No previous cases of ML have been reported in our country as we review the literature concerning this disease.

Assignment of the locus for PLO-SL, a frontal-lobe dementia with bone cysts, to 19q13

PLO-SL (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy) is a recessively inherited disorder characterized by systemic bone cysts and progressive presenile frontal-lobe dementia, resulting in death at <50 years of age. Since the 1960s, approximately 160 cases have been reported, mainly in Japan and Finland. The pathogenesis of the disease is unknown. In this article, we report the assignment of the locus for PLO-SL, by random genome screening using a modification of the haplotype-sharing method, in patients from a genetically isolated population. By screening five patient samples from 2 Finnish families, followed by linkage analysis of 12 Finnish families, 3 Swedish families, and 1 Norwegian family, we were able to assign the PLO-SL locus to a 9-cM interval between markers D19S191 and D19S420 on chromosome 19q13. The critical region was further restricted, to approximately 1.8 Mb, by linkage-disequilibrium analysis of the Finnish families. According to the haplotype analysis, one Swedish and one Norwegian PLO-SL family are not linked to the chromosome 19 locus, suggesting that PLO-SL is a heterogeneous disease. In this chromosomal region, one potential candidate gene for PLO-SL, the gene encoding amyloid precursor-like protein 1, was analyzed, but no mutations were detected in the coding region.

Nasu-Hakola syndrome: polycystic lipomembranous osteodysplasia with sclerosing leucoencephalopathy and presenile dementia

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