GENETIC DERMINATION OF PPH EXPRESSION

Vanderbilt University, Nashville TN

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Abstract

Primary pulmonary hypertension (PPH) is a disease of small pulmonary arteries which can be familial (FPPH) or sporadic. Mutations in the bone morphogenic protein receptor 2 (BMPR2) gene cause a major proportion of both FPPH and sporadic PPH. Heterogeneous mutations have been reported in the exons of BMPR2 in ~50% and ~25% of familial and sporadic cases, respectively. Using stress echocardiography others obtained linkage data suggesting that a second, nearby locus may also cause FPPH. The penetrance of FPPH is only ~20% in our families. Studies of dissected lesions from FPPH lungs show clonality suggesting that loss of heterozygosity (LOH) and/or somatic mutations which may indicate that a two hit model underlies the reduced penetrance of FPPH. While multiple FPPH families exhibit genetic anticipation (earlier onset of disease in successive generations), no BMPR2 allelic changes have been reported that explain anticipation. We hypothesize that 1) allelic heterogeneity in BMPR2 causes many of the FPPH and sporadic cases in which BMPR2 mutations have not been identified, 2) variation in nuclear or mitochondrial modifier genes, LOH and/or acquired somatic imutations contribute to the reduced penetrance of FPPH, 3) variations in BMPR2 or a modifier gene cause the anticipation seen in FPPH, and 4) locus heterogeneity may contribute to the etiology of FPPH. To better understand the molecular basis of PPH we will determine the allelic heterogeneity that exists in the BMPR2 alleles of various FPPH kindreds and sporadic cases, identify and characterize variations in modifier genes or somatic changes in BMPR2 that affect the penetrance of FPPH, identify genetic alterations that may cause anticipation in FPPH and determine if locus heterogeneity exists in our families (locus heterogeneity will be examined in Project 1). Our studies are of general interest because they will provide insight to the pathogenesis of an important autosomal dominant disease that exhibits variable expression, reduced penetrance and anticipation. Vanderbilt University Medical Center Division of Pediatric Medical Genetics DD-2205 Medical Center North Nashville, TN 37232-2578 KEY PERSONNEL. See instructions. Use continuation Investigator. List all other key personnel in alphabetical Name Phillips, John A., HI, M.D. Gaddipatti, Radhika, M.B.B.S. Lane, Kirk B., Ph.D. Vnencak-Jones, Cindy, Ph.D. pages as needed to provide the required information order, last name first. Organization Vanderbilt University Medical Center Vanderbilt University Medical Center Vanderbilt University Medical Center Vanderbilt University Medical Center PHS 398 (Rev. 05/01) _ Page 19 8 Number pages consecutively at the bottom throughout the application, uo not use suffices such as 3a, 3b. in the format shown below. Start with Principal Role on Project Project Leader Investigator Investigator Investigator Form Page 2 O Project III: Genetic Determination of PPH Expression Principal Investigator/Program Director (Last, first, middle): Loyd I James E.v M.D. FROM THROUGH DETAILED BUDGET FOR INITIAL BUDGET PERIOD DIRECT COSTS ONLY 7/1/2003 6/30/2004 PERSONNEL (Applicant orgam'zabbn only) % DOLLAR AMOUNT REQUESTED(omit cents) TYPE EFFORT INST. NAME ROLE ON APPT ON BASE SALARY FRINGE PROJECT (months) PROJ. SALARY REQUESTED BENEFTTS TOTALS Principal John Phillips, M.D. 12 25% 166,700 41,675 6,626 48,301 Investigator Kirk B. Lane, Ph.D. Investigator 12 30% 93,600 28,080 6,318 34,398 Cindy Vnencak-]ones, Ph.D. Investigator 12 5% 109,101 5,455 1,227 6,682 Deborah Murdock Ph.D. Investigator 12 10% 75,400i 7,540 1,697 9,237 Melissa Prince Lab Mgr 12 30% 45,125 13,538 3,466 17,004 Radhika Gaddipatti Fellow 12 25% 46,188 11,547 2,956 14,503 Thomas Blackwell Lab Mgr 12 25% 40,372 10,093 2,584 12,677 To be announced Res Asst III 12 100% 37,500 37,500 9,600 47,100 Kuisook Keel Technologist 12 5% 30,623 1,531 392 1,923 To be announced Res Asst II 12 100% 32,500 32,500 8,320 40,820 SUBTOTALS 189,459 43,186 232,645 CONSULTANT COSTS 0 EQUIPMENT (Itemize) 0 SUPPLIES (Itemize by category) Genotyping for Anticipation Studies 7,000 Genotyping and Sequencing for BMPR2 studies 27,000 LOH Study Supplies 400 Southern Blotting Supplies 600 Tissue Culture Supplies 15,000 Molecular Biology Supplies (disposables, plastics, glassware, pipettes, etc) 14,500 General Lab Supplies 11,000 75,500 TRAVEL 0 PATIENT CARE COSTS 0 INPATIENT OUTPATIENT 0 ALTERATIONS AND RENOVATIONS (itemize by category) None 0 OTHER EXPENSES (Itemize by category) Software Upgrades 1,000 lf000 SUBTOTAL DIRECT COSTS FOR INITIAL BUDGET PERIOD $30e,1451 0 CONSORTIUM/CONTRACTUAL DIRECT COSTS COSTS FACILITIES AND ADMINISTRATION COSTS 0 TOTAL DIRECT COSTS FOR INITIAL BUDGET PERIOD (Item7a,FacePage) $309,1451 SBIR/STTR Only: FIXED FEE REQUESTED PHS398(Rev.05/01) (Page) 19 9 Form Page 4 Number pages consecutivelyat the bottom throughoutthe application. Do not usesuffixes such as 3a, 3b.