BACKGROUND The Proteus syndrome is characterized by the overgrowth of skin, connective tissue, brain, and other tissues. It has been hypothesized that the syndrome is caused by somatic mosaicism for a mutation that is lethal in the nonmosaic state. METHODS We performed exome sequencing of DNA from biopsy samples obtained from patients with the Proteus syndrome and compared the resultant DNA sequences with those of unaffected tissues obtained from the same patients. We confirmed and extended an observed association, using a custom restriction-enzyme assay to analyze the DNA in 158 samples from 29 patients with the Proteus syndrome. We then assayed activation of the AKT protein in affected tissues, using phosphorylation-specific antibodies on Western blots. RESULTS Of 29 patients with the Proteus syndrome, 26 had a somatic activating mutation (c.49G→A, p.Glu17Lys) in the oncogene AKT1, encoding the AKT1 kinase, an enzyme known to mediate processes such as cell proliferation and apoptosis. Tissues and cell lines from patients with the Proteus syndrome harbored admixtures of mutant alleles that ranged from 1% to approximately 50%. Mutant cell lines showed greater AKT phosphorylation than did control cell lines. A pair of single-cell clones that were established from the same starting culture and differed with respect to their mutation status had different levels of AKT phosphorylation. CONCLUSIONS The Proteus syndrome is caused by a somatic activating mutation in AKT1, proving the hypothesis of somatic mosaicism and implicating activation of the PI3K–AKT pathway in the characteristic clinical findings of overgrowth and tumor susceptibility in this disorder. (Funded by the Intramural Research Program of the National Human Genome Research Institute.)
Somatic mutations in the phosphatidylinositol/AKT/mTOR pathway cause segmental overgrowth disorders. Diagnostic descriptors associated with PIK3CA mutations include fibroadipose overgrowth (FAO), Hemihyperplasia multiple Lipomatosis (HHML), Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi, Scoliosis/skeletal and spinal (CLOVES) syndrome, macrodactyly, and the megalencephaly syndrome, Megalencephaly-Capillary malformation (MCAP) syndrome. We set out to refine the understanding of the clinical spectrum and natural history of these phenotypes, and now describe 35 patients with segmental overgrowth and somatic PIK3CA mutations. The phenotypic data show that these previously described disease entities have considerable overlap, and represent a spectrum. While this spectrum overlaps with Proteus syndrome (sporadic, mosaic, and progressive) it can be distinguished by the absence of cerebriform connective tissue nevi and a distinct natural history. Vascular malformations were found in 15/35 (43%) and epidermal nevi in 4/35 (11%) patients, lower than in Proteus syndrome. Unlike Proteus syndrome, 31/35 (89%) patients with PIK3CA mutations had congenital overgrowth, and in 35/35 patients this was asymmetric and disproportionate. Overgrowth was mild with little postnatal progression in most, while in others it was severe and progressive requiring multiple surgeries. Novel findings include: adipose dysregulation present in all patients, unilateral overgrowth that is predominantly left-sided, overgrowth that affects the lower extremities more than the upper extremities and progresses in a distal to proximal pattern, and in the most severely affected patients is associated with marked paucity of adipose tissue in unaffected areas. While the current data are consistent with some genotype–phenotype correlation, this cannot yet be confirmed. © The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals, Inc.
onset in infancy (SAVI), and another by additive loss-of-function mutations in proteasome genes causing the proteasome-associated autoinflammatory syndromes (PRAAS) (also, chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperatures [CANDLE]), presented with chronically elevated interferon (IFN) signatures, suggesting a pathogenic role for type-I IFN in autoinflammatory diseases (2, 3). Type-I IFN was first discovered as a soluble antiviral factor over 50 years ago, and a role in sterile inflammation was proposed in patients with systemic lupus erythematosus (4). However, the discovery of genetic mutations that cause the autoinflammatory type-I interferonopathies CANDLE (2, 5), SAVI (3, 6-8), and Aicardi-Goutières syndrome (AGS) (9, 10) have shed light on pathomechanisms that drive chronic IFN signaling, and recent studies blocking IFN signaling validate a critical role for type-I IFNs (11). AGS-causing loss-of-function mutations in nucleases impair self-nucleic acid homeostasis, SAVI-causing
Osteoporosis‐related fractures are undertreated, due in part to misinformation about recommended approaches to patient care and discrepancies among treatment guidelines. To help bridge this gap and improve patient outcomes, the American Society for Bone and Mineral Research assembled a multistakeholder coalition to develop clinical recommendations for the optimal prevention of secondary fracture among people aged 65 years and older with a hip or vertebral fracture. The coalition developed 13 recommendations (7 primary and 6 secondary) strongly supported by the empirical literature. The coalition recommends increased communication with patients regarding fracture risk, mortality and morbidity outcomes, and fracture risk reduction. Risk assessment (including fall history) should occur at regular intervals with referral to physical and/or occupational therapy as appropriate. Oral, intravenous, and subcutaneous pharmacotherapies are efficacious and can reduce risk of future fracture. Patients need education, however, about the benefits and risks of both treatment and not receiving treatment. Oral bisphosphonates alendronate and risedronate are first‐line options and are generally well tolerated; otherwise, intravenous zoledronic acid and subcutaneous denosumab can be considered. Anabolic agents are expensive but may be beneficial for selected patients at high risk. Optimal duration of pharmacotherapy is unknown but because the risk for second fractures is highest in the early post‐fracture period, prompt treatment is recommended. Adequate dietary or supplemental vitamin D and calcium intake should be assured. Individuals being treated for osteoporosis should be reevaluated for fracture risk routinely, including via patient education about osteoporosis and fractures and monitoring for adverse treatment effects. Patients should be strongly encouraged to avoid tobacco, consume alcohol in moderation at most, and engage in regular exercise and fall prevention strategies. Finally, referral to endocrinologists or other osteoporosis specialists may be warranted for individuals who experience repeated fracture or bone loss and those with complicating comorbidities (eg, hyperparathyroidism, chronic kidney disease). © 2019 American Society for Bone and Mineral Research.
BackgroundA better understanding of the natural history of osteogenesis imperfecta (OI) in adulthood should improve health care for patients with this rare condition.MethodsThe Osteogenesis Imperfecta Foundation established the Adult Natural History Initiative (ANHI) in 2010 to give voice to the health concerns of the adult OI community and to begin to address existing knowledge gaps for this condition. Using a web-based platform, 959 adults with self-reported OI, representing a wide range of self-reported disease severity, reported symptoms and health conditions, estimated the impact of these concerns on present and future health-related quality of life (QoL) and completed a Patient-Reported Outcomes Measurement Information System (PROMIS®) survey of health issues.ResultsAdults with OI report lower general physical health status (p < .0001), exhibit a higher prevalence of auditory (58 % of sample versus 2–16 % of normalized population) and musculoskeletal (64 % of sample versus 1–3 % of normalized population) concerns than the general population, but report generally similar mental health status. Musculoskeletal, auditory, pulmonary, endocrine, and gastrointestinal issues are particular future health-related QoL concerns for these adults. Numerous other statistically significant differences exist among adults with OI as well as between adults with OI and the referent PROMIS® population, but the clinical significance of these differences is uncertain.ConclusionsAdults with OI report lower general health status but are otherwise more similar to the general population than might have been expected. While reassuring, further analysis of the extensive OI-ANHI databank should help identify areas of unique clinical concern and for future research. The OI-ANHI survey experience supports an internet-based strategy for successful patient-centered outcomes research in rare disease populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-015-0362-2) contains supplementary material, which is available to authorized users.
The Own the Bone initiative offers tools to improve the prevention of secondary fractures and a structure to monitor physician compliance. The American Orthopaedic Association plans to use these quality-improvement tools to stimulate change in both physician and patient behavior following low-energy fractures.
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