![]() Augustine, Trinidad & Tobago, West IndiesCorrespondence: Patrick Harnarayan, Department of Clinical Surgical Sciences, University of The West Indies, St. Patrick Harnarayan, Dave Harnanan Department of Clinical Surgical Sciences, University of The West Indies, St. Patients N7 and N99 were positive for the p.His1047Arg mutation in PIK3CA, PS53 and PS75 were positive for the p.Glu17Lys mutation in AKT1 (ref. Fibroblasts were serum starved for 24 hours before solubilization. Infrared detection of phosphorylated and total AKT in patients with PIK3CA or AKT1 mutations. Representative immunoblot showing abnormal basal phosphorylation of AKT and p70 S6 kinase (p70S6K) in affected dermal fibroblasts (B) but no increase in basal ERK phosphorylation (C). * = Significantly higher than unstimulated unaffected cells (p<0.01) ∞ = significantly higher than EGF-stimulated unaffected cells (p<0.01) # = not significantly different error bars are + 2 SEM. Cells from a healthy control (Cntrl), Patient C1 (unaffected arm and affected leg) and from patients N7 and N99 (both affected) are shown. PIP3 levels determined by mass spectroscopy are elevated in fibroblasts harboring an activating PIK3CA mutation both in the basal state and after stimulation with EGF compared to unaffected cells. Hyperactivity of phosphatidylinositol-3-kinase in cells harboring PIK3CA mutations A. (o,p) Plain radiograph (o) and photograph (p) of the left foot of subject N110, showing overgrowth limited to the first and second rays of the left foot. (n) Plain radiograph of the hand of subject N68, showing distorting overgrowth of the second and third rays of the right hand. (i–m) Imaging of subject N45, showing fibroadipose overgrowth of the legs, including subcutaneous and muscular tissue in coronal (i) and transverse (k) views, fibroadipose overgrowth of the pelvis (j) and plain radiographs of the normal right knee (l) and distorting overgrowth of the left knee (m). (g,h) Muscle is replaced by fibrous and adipose tissue, with occasional residual muscle fibers (arrow) in affected tissue (g) relative to normal muscle (h). Inset, myofibroblasts with plump nuclei are prominent in the dermis (arrow). #Overgrowth free 206 free download skin#(e,f) Hematoxylin and eosin staining of left foot skin (e) and normal skin (f), showing marked dermal thickening in e. (c,d) Transverse CT image (c) and photograph (d) of anterior abdomen, showing right-sided adipose overgrowth (arrow) and left-sided lack of adipose tissue (arrowhead) to the level of insertion of erector spinae. Normal nerve roots in this region are up to 5–6 mm in diameter and up to 8–9 mm in diameter for the dorsal root ganglion31. (b) Sagittal T2-weighted MRI of the lumbar spine, showing enlarged neural structures within the foramina (circles of 12–13 mm in diameter). (a) Reformatted coronal computed tomography (CT) scan of the legs, showing bony overgrowth, destructive arthropathy, adipose expansion and relative lack of muscle. Segmental skeletal and fibroadipose overgrowth in individuals with activating PIK3CA mutations. Our findings characterize a distinct overgrowth syndrome, biochemically demonstrate activation of PI3K signaling and thereby identify a rational therapeutic target. Affected dermal fibroblasts showed enhanced basal and epidermal growth factor (EGF)-stimulated phosphatidylinositol 3,4,5-trisphosphate (PIP(3)) generation and concomitant activation of downstream signaling relative to their unaffected counterparts. Sequencing of PIK3CA in ten additional individuals with overlapping syndromes identified either the p.His1047Leu alteration or a second cancer-associated alteration, p.His1047Arg, in nine cases. We performed exome sequencing of DNA from unaffected and affected cells from an individual with an unclassified syndrome of congenital progressive segmental overgrowth of fibrous and adipose tissue and bone and identified the cancer-associated mutation encoding p.His1047Leu in PIK3CA, the gene that encodes the p110α catalytic subunit of PI3K, only in affected cells. Correspondingly, loss of function of PTEN, a negative regulator of PI3K, or activating mutations in AKT1, AKT2 or AKT3 have been found in distinct disorders featuring overgrowth or hypoglycemia. The phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway is critical for cellular growth and metabolism. ![]()
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