[show abstract][hide abstract] ABSTRACT: Adolescent idiopathic scoliosis (AIS) is an unexplained and common spinal deformity seen in otherwise healthy children. Its pathophysiology is poorly understood despite intensive investigation. Although genetic underpinnings are clear, replicated susceptibility loci that could provide insight into etiology have not been forthcoming. To address these issues, we performed genome-wide association studies (GWAS) of ∼327 000 single nucleotide polymorphisms (SNPs) in 419 AIS families. We found strongest evidence of association with chromosome 3p26.3 SNPs in the proximity of the CHL1 gene (P < 8 × 10(-8) for rs1400180). We genotyped additional chromosome 3p26.3 SNPs and tested replication in two follow-up case-control cohorts, obtaining strongest results when all three cohorts were combined (rs10510181 odds ratio = 1.49, 95% confidence interval = 1.29-1.73, P = 2.58 × 10(-8)), but these were not confirmed in a separate GWAS. CHL1 is of interest, as it encodes an axon guidance protein related to Robo3. Mutations in the Robo3 protein cause horizontal gaze palsy with progressive scoliosis (HGPPS), a rare disease marked by severe scoliosis. Other top associations in our GWAS were with SNPs in the DSCAM gene encoding an axon guidance protein in the same structural class with Chl1 and Robo3. We additionally found AIS associations with loci in CNTNAP2, supporting a previous study linking this gene with AIS. Cntnap2 is also of functional interest, as it interacts directly with L1 and Robo class proteins and participates in axon pathfinding. Our results suggest the relevance of axon guidance pathways in AIS susceptibility, although these findings require further study, particularly given the apparent genetic heterogeneity in this disease.
Human Molecular Genetics 01/2011; 20(7):1456-66. · 7.69 Impact Factor
[show abstract][hide abstract] ABSTRACT: PAPA syndrome (Pyogenic Arthritis, Pyoderma gangrenosum, and Acne) is an autosomal dominant, hereditary auto-inflammatory disease arising from mutations in the PSTPIP1/CD2BP1 gene on chromosome 15q. These mutations produce a hyper-phosphorylated PSTPIP1 protein and alter its participation in activation of the "inflammasome" involved in interleukin-1 (IL-1β) production. Overproduction of IL-1β is a clear molecular feature of PAPA syndrome. Ongoing research is implicating other biochemical pathways that may be relevant to the distinct pyogenic inflammation of the skin and joints characteristic of this disease. This review summarizes the recent and rapidly accumulating knowledge on these molecular aspects of PAPA syndrome and related disorders.
Current Genomics 11/2010; 11(7):519-27. · 2.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: Idiopathic scoliosis (AIS) is the most common pediatric spinal deformity, affecting ~3% of children worldwide. AIS significantly impacts national health in the U. S. alone, creating disfigurement and disability for over 10% of patients and costing billions of dollars annually for treatment. Despite many investigations, the underlying etiology of IS is poorly understood. Twin studies and observations of familial aggregation reveal significant genetic contributions to IS. Several features of the disease including potentially strong genetic effects, the early onset of disease, and standardized diagnostic criteria make IS ideal for genomic approaches to finding risk factors. Here we comprehensively review the genetic contributions to IS and compare those findings to other well-described complex diseases such as Crohn's disease, type 1 diabetes, psoriasis, and rheumatoid arthritis. We also summarize candidate gene studies and evaluate them in the context of possible disease aetiology. Finally, we provide study designs that apply emerging genomic technologies to this disease. Existing genetic data provide testable hypotheses regarding IS etiology, and also provide proof of principle for applying high-density genome-wide methods to finding susceptibility genes and disease modifiers.
Current Genomics 04/2008; 9(1):51-9. · 2.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: Gain/loss of function studies were utilized to assess the potential role of the endogenous vanilloid receptor TRPV4 as a sensor of flow and osmolality in M-1 collecting duct cells (CCD). TRPV4 mRNA and protein were detectable in M-1 cells and stably transfected HEK-293 cells, where the protein occurred as a glycosylated doublet on Western blots. Immunofluorescence imaging demonstrated expression of TRPV4 at the cell membranes of TRPV4-transfected HEK and M-1 cells and at the luminal membrane of mouse kidney CCD. By using intracellular calcium imaging techniques, calcium influx was monitored in cells grown on coverslips. Application of known activators of TRPV4, including 4alpha-PDD and hypotonic medium, induced strong calcium influx in M-1 cells and TRPV4-transfected HEK-293 cells but not in nontransfected cells. Applying increased flow/shear stress in a parallel plate chamber induced calcium influx in both M-1 and TRPV4-transfected HEK cells but not in nontransfected HEK cells. Furthermore, in loss-of-function studies employing small interference (si)RNA knockdown techniques, transfection of both M-1 and TRPV4-transfected HEK cells with siRNA specific for TRPV4, but not an inappropriate siRNA, led to a time-dependent decrease in TRPV4 expression that was accompanied by a loss of stimuli-induced calcium influx to flow and hypotonicity. It is concluded that TRPV4 displays a mechanosensitive nature with activation properties consistent with a molecular sensor of both fluid flow (or shear stress) and osmolality, or a component of a sensor complex, in flow-sensitive renal CCD.
American journal of physiology. Renal physiology 12/2007; 293(5):F1699-713. · 3.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: Idiopathic scoliosis (IS) is the most common spinal deformity in children, and its etiology is unknown. To refine the search for genes underlying IS susceptibility, we ascertained a new cohort of 52 families and conducted a follow-up study of genomewide scans that produced evidence of linkage and association with 8q12 loci (multipoint LOD 2.77; P=.0028). Further fine mapping in the region revealed significant evidence of disease-associated haplotypes (P<1.0 x 10-4) centering over exons 2-4 of the CHD7 gene associated with the CHARGE (coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness) syndrome of multiple developmental anomalies. Resequencing CHD7 exons and conserved intronic sequence blocks excluded coding changes but revealed at least one potentially functional polymorphism that is overtransmitted (P=.005) to affected offspring and predicts disruption of a caudal-type (cdx) transcription-factor binding site. Our results identify the first gene associated with IS susceptibility and suggest etiological overlap between the rare, early-onset CHARGE syndrome and common, later-onset IS.
The American Journal of Human Genetics 05/2007; 80(5):957-65. · 11.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: The TRPV4 calcium-permeable channel was cloned from mouse kidney M-1 cells, and the effect of temperature modulation on channel gating/activation by physical and chemical signals was evaluated. A TRPV4 cDNA construct with a C-terminal V5 epitope was stably transfected into human embryonic kidney (HEK) 293 and Chinese hamster ovary cells resulting in high levels of expression at the plasma membrane. Channel activation was assessed from changes in calcium influx (fura-2 fluorescence measurements) or whole cell currents (patch clamp analysis). At room temperature (22-24 degrees C), exposure of TRPV4-transfected cells to hypotonic medium (225 mOsm/liter) or a non-protein kinase C (PKC)-activating phorbol ester derivative, 4alpha-phorbol 12,13-decanoate (100 nm), induces modest channel activation, whereas phorbol 12-myristate 13-acetate (100 nm), a PKC-activating phorbol ester, and shear stress (3-20 dyne/cm2) had minimal or no effect on channel activation. In contrast, at elevated temperatures (37 degrees C) the channel was rapidly activated by all stimuli. Inhibition of PKC by calphostin C (50 nm) or staurosporine (500 nm) abolished phorbol 12-myristate 13-acetate-induced activation of the channel without affecting the response to other stimuli. Ruthenium red (1 microm) effectively blocked the channel activity by all stimuli. It is concluded that temperature is a critical modulator of TRPV4 channel gating, leading to activation of the channel by a diverse range of microenvironmental chemical and physical signals utilizing a least two transduction pathways, one PKC-dependent and one PKC-independent. The convergence of multiple signals and transduction pathways on the same channel indicate that the channel functions as a molecular integrator of microenvironmental chemical and physical signals.
Journal of Biological Chemistry 08/2003; 278(29):27129-37. · 4.65 Impact Factor