Method of diagnosing pulmonary hypertension

#This invention relates generally to a method of identifying an individual having an increased susceptibility to developing Familial Primary Pulmonary Hypertension (FPPH), as well as to a method for diagnosing an individual suffering from FPPH. The invention also relates to a method of identifying an individual having an increased susceptibility to developing non-familial, or sporadic, Primary Pulmonary Hypertension (PPH), as well as to a method for diagnosing an individual suffering from sporadic PPH. The invention also relates to a method of identifying an agent capable of altering the symptoms of PPH in an individual suffering from familial or sporadic PPH, comprising contacting a test agent with Bone Morphogenic Protein Receptor II (BMPR-II) and determining whether the test agent alters BMPR-II activity, wherein an alteration in BMPR-II activity in the presence of the test agent as compared with BMPR-II activity in the absence of the test agent indicates that the test agent is capable of altering the symptoms of PPH in an individual suffering from familial or sporadic PPH.

#Primary pulmonary hypertension (PH) is characterized by sustained elevation of pulmonary artery pressure (greater than 25 mmHg at rest and greater than 30 mmHg during exercise) and with no identifiable cause, such as recurrent thromboembolism, chronic hypoxic lung disease or left-sided cardiac disease. PPH is twice as common in females than males and symptoms develop typically in the 3rd and 4th decades of life, although the disease may occur at any age. Despite advances in therapy, mortality in PPH remains high with mean survival from onset of disease only 2.5 year.

#At least 6% of individuals diagnosed with PPH have a known family history of the disorder. The disease can be classified as being either familial (more than one affected relative has been identified in at least 6% of cases (familial PPH; MIM 178600) (ref. 3)) or sporadic. Familial PPH (FPPH) segregates as an autosomal dominant disorder, with markedly reduced penetrance.

#FIGS. 1A-1C are diagrams showing the physical map of the PPH1 interval at 2q33. FIG. 1A shows the position of microsatellite markers. The markers are, from left to right, D2S115, D2S348, D2S2392, D2S2396, D2S1367, D2S116, D2S309, D2S2309, D2S2214, D2S2217, D2S346, D2S2289, 19E07, D2S307, CTLA4, D2S72, D2S105, D2S2189, D2S1384. FIG. 1B shows the physical map contig (BAC/PAC) of the region surrounding BMPR2 including other genes analysed in the examples (12). FIG. 1C shows the BMPR2 genomic structure, determined by analysis of available sequence data for BAC clone RP11-345N12 as well as sequence analysis of additional BAC clones identified by library screening as shown (not to scale).

#FIG. 2A is a diagram of the structure of BMPR2 cDNA. The location of the exons are indicated by the nucleotide start position in the cDNA. The cysteine residues within the extracellular domain are each denoted by *. The filled in box represents the transmembrane domain and the stippled area identifies the region encoding the receptor kinase domain.

#FIG. 2B is a diagram of BLAST homology results showing protein similarity of human BMPR-II with receptors in other species and human TGF-β receptor type II (TGFBR-II). Amino acid positions are shown together with the codon substitutions of conserved amino acids (boxed).

#The invention relates to the surprising discovery that FPPH is caused by mutations in the gene encoding a TGF-β type II receptor, BMPR-II. The invention provides a method of identifying a subject having an increased susceptibility for developing pulmonary hypertension, comprising detecting a mutant Bone Morphogenic Protein Receptor II (BMPR-II) polypeptide or a mutated BMPR2 nucleic acid in the subject, thereby identifying a subject having an increased susceptibility for developing pulmonary hypertension. BMPR2 refers to the gene (or other nucleic acid) encoding a BMPR-II polypeptide. BMPR-II refers to the polypeptide encoded by a BMPR2 gene. Both of these terms are used herein as general identifiers. Thus, for example, a BMPR2 gene or nucleic acid refers to any gene or nucleic acid identified with or derived from a wild-type BMPR2 gene. For example, a mutant BMPR2 gene is a form of BMPR2 gene.

#In a preferred embodiment, the pulmonary hypertension is primary pulmonary hypertension. In another embodiment, the pulmonary hypertension is secondary pulmonary hypertension.

#As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, “a molecule” can mean a single molecule or more than one molecule.