High frequency of BMPR2 exonic deletions/duplications in familial pulmonary arterial hypertension.
BACKGROUND
Previous studies have shown that approximately 55% of patients with familial pulmonary arterial hypertension (FPAH) have BMPR2 coding sequence mutations. However, direct sequencing does not detect other types of heterozygous mutations, such as exonic deletions/duplications.


OBJECTIVE
To estimate the frequency of BMPR2 exonic deletions/duplications in FPAH.


METHODS
BMPR2 mRNA from lymphoblastoid cell lines of 30 families with PAH and 14 patients with idiopathic PAH (IPAH) was subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing. Sequencing of genomic DNA was used to identify point mutations in splice donor/acceptor sites. Multiplex ligation-dependent probe amplification (MLPA) was used to detect exonic deletions/duplications with verification by real-time PCR.


RESULTS
Eleven (37%) patients with FPAH had abnormally sized RT-PCR products. Four of the 11 patients were found to have splice-site mutations resulting in aberrant splicing, and exonic deletions/duplications were detected in the remaining seven patients. MLPA identified three deletions/duplications that were not detectable by RT-PCR. Coding sequence point mutations were identified in 11 of 30 (37%) patients. Mutations were identified in 21 of 30 (70%) patients with FPAH, with 10 of 21 mutations (48%) being exonic deletions/duplications. Two of 14 (14%) patients with IPAH exhibited BMPR2 point mutations, whereas none showed exonic deletions/duplications.


CONCLUSIONS
Our study indicates that BMPR2 exonic deletions/duplications in patients with FPAH account for a significant proportion of mutations (48%) that until now have not been screened for. Because the complementary approach used in this study is rapid and cost effective, screening for BMPR2 deletions/duplications by MLPA and real-time PCR should accompany direct sequencing in all PAH testing.
Cogan
Joy D
JD
Division of Medical Genetics, Vanderbilt University Medical University Medical Center, Nashville, Tennessee, USA.
Pauciulo
Michael W
MW
Batchman
Amy P
AP
Prince
Melissa A
MA
Robbins
Ivan M
IM
Hedges
Lora K
LK
Stanton
Krista C
KC
Wheeler
Lisa A
LA
Phillips
John A
JA
Loyd
James E
JE
Nichols
William C
WC
D052006:Bone Morphogenetic Protein Receptors, Type II / Q000235:genetics*; D016022:Case-Control Studies; D005091:Exons / Q000235:genetics*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques; D022821:RNA Splice Sites / Q000235:genetics; D017421:Sequence Analysis
D022821:RNA Splice Sites; C498218:BMPR2 protein, human; D052006:Bone Morphogenetic Protein Receptors, Type II