Gross BMPR2 gene rearrangements constitute a new cause for primary pulmonary hypertension.
OBJECTIVE
Approximately 50% of patients with familial primary pulmonary hypertension (FPPH) have been reported to have mutations within the bone morphogenic protein receptor type 2 (BMPR2) gene. The vast majority of these mutations were identified by PCR amplification and sequencing of individual exons. The aim of our study was to determine if additional BMPR2 mutations not found by exon sequencing alone could account for a significant portion of these negative cases.


METHODS
We examined DNA samples from 12 families, previously found to be negative for BMPR2 mutations, to identify any large BMPR2 gene rearrangements.


RESULTS
Southern blot analysis found large gene rearrangements in four (33%) unrelated kindreds. Further analysis by reverse transcriptase PCR (RT-PCR) of BMPR2 transcripts from two of these kindreds found one to be heterozygous for a exon 10 duplication and the second to be heterozygous for a deletion of exons 4 to 5. Nonhomologous recombination is believed to be the cause of these large insertions/deletions.


CONCLUSIONS
Our results demonstrate the inherent problems associated with exon-by-exon sequencing and the importance of other screening methods such as Southern blot and RT-PCR in the identification of BMPR2 mutations.
Cogan
Joy D
JD
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2578, USA.
Vnencak-Jones
Cindy L
CL
Phillips
John A
JA
Lane
Kirk B
KB
Wheeler
Lisa A
LA
Robbins
Ivan M
IM
Garrison
Gladys
G
Hedges
Lora K
LK
Loyd
James E
JE
D000293:Adolescent; D000328:Adult; D015139:Blotting, Southern; D052006:Bone Morphogenetic Protein Receptors, Type II; D002648:Child; D005091:Exons / Q000235:genetics; D005260:Female; D015321:Gene Rearrangement; D006579:Heterozygote; D006801:Humans; D006976:Hypertension, Pulmonary / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D017346:Protein Serine-Threonine Kinases; C498218:BMPR2 protein, human; D052006:Bone Morphogenetic Protein Receptors, Type II