Marfan syndrome (MFS), one of the most common genetic disorders of connective tissue, is characterized by skeletal, cardiovascular and ocular abnormalities. The incidence of the disease is about 1 in 20,000, with life expectancy severely reduced because of cardiovascular complications. As the underlying defect is unknown, MFS diagnosis is based solely on clinical criteria. Certain phenotypic features of MFS are also shared by other conditions, which may be genetically distinct entities although part of a clinical continuum. Immunohistochemical studies have implicated fibrillin, a major component of elastin-associated microfibrils, in MFS aetiology. Genetic linkage analysis with random probes has independently localized the MFS locus to chromosome 15. Here we report that these two experimental approaches converge with the cloning and mapping of the fibrillin gene to chromosome 15q15-21, and with the establishment of linkage to MFS. We also isolated a second fibrillin gene and mapped it to chromosome 5q23-31. We linked this novel gene to a condition, congenital contractural arachnodactyly, that shares some of the features of MFS. Thus, the cosegregation of two related genes with two related syndromes implies that fibrillin mutations are likely to be responsible for different MFS phenotypes.

Wilson disease (WD) is an autosomal recessive disorder of copper transport which map to chromosome 13q14.3. In pursuit of the WD gene, we developed yeast artificial chromosome and cosmid contigs, and microsatellite markers which span the WD gene region. Linkage disequilibrium and haplotype analysis of 115 WD families confined the disease locus to a single marker interval. A candidate cDNA clone was mapped to this interval which, as shown in the accompanying paper, is very likely the WD gene. Our haplotype and mutation analyses predict that approximately half of all WD mutations will be rare in the American and Russian populations.

The Marfan syndrome appears to be caused by mutations in a single fibrillin gene on chromosome 15. Diagnosis of the Marfan syndrome by genetic linkage and analysis is now feasible in many families.

BackgroundAlthough the mechanisms underlying AD neurodegeneration are not fully understood, it is now recognised that inflammation could play a crucial role in the initiation and progression of AD neurodegeneration. A neuro-inflammatory network, based on the anomalous activation of microglial cells, includes the production of a number of inflammatory cytokines both locally and systemically. These may serve as diagnostic markers or therapeutic targets for AD neurodegeneration.MethodsWe have measured the levels of the inflammation-related cytokines and receptors of the IL-1 family in serum of subjects with AD, compared to mild cognitive impairment (MCI), subjective memory complaints (SMC), and normal healthy subjects (NHS). Using a custom-made multiplex ELISA array, we examined ten factors of the IL-1 family, the inflammation-related cytokines IL-1α, IL-1β, IL-18, and IL-33, the natural inhibitors IL-1Ra and IL-18BP, and the soluble receptors sIL-1R1, sIL-1R2, sIL-1R3, and sIL-1R4.ResultsThe inflammatory cytokines IL-1α and IL-1β, their antagonist IL-1Ra, and their soluble receptor sIL-1R1 were increased in AD. The decoy IL-1 receptor sIL-1R2 was only increased in MCI. IL-33 and its soluble receptor sIL-1R4 were also significantly higher in AD. The soluble form of the accessory receptor for both IL-1 and IL-33 receptor complexes, sIL-1R3, was increased in SMC and even more in AD. Total IL-18 levels were unchanged, whereas the inhibitor IL-18BP was significantly reduced in MCI and SMC, and highly increased in AD. The levels of free IL-18 were significantly higher in MCI.ConclusionsAD is characterised by a significant alteration in the circulating levels of the cytokines and receptors of the IL-1 family. The elevation of sIL-1R4 in AD is in agreement with findings in other diseases and can be considered a marker of ongoing inflammation. Increased levels of IL-1Ra, sIL-1R1, sIL-1R4, and IL-18BP distinguished AD from MCI and SMC, and from other inflammatory diseases. Importantly, sIL-1R1, sIL-1R3, sIL-1R4, and IL-18BP negatively correlated with cognitive impairment. A significant elevation of circulating sIL-1R2 and free IL-18, not present in SMC, is characteristic of MCI and disappears in AD, making them additional interesting markers for evaluating progression from MCI to AD.Electronic supplementary materialThe online version of this article (10.1186/s12974-018-1376-1) contains supplementary material, which is available to authorized users.