PRKAR1A gene mutation in patients with cardiac myxoma

PRKAR1A gene encodes the type 1A regulatory subunit of protein kinase A. The mutation of this gene causes Carney complex which is an autosomal dominant multiple neoplasia syndrome characterized by spotty pigmentations, endocrine overactivity and cardiac myxoma. We hypothesized that cardiac myxoma may be associated with PRKAR1A gene mutation and determined whether mutation in the PRKAR1A gene is the cause of familial and sporadic cardiac myxoma.

We studied seven patients (three males and four females) with cardiac myxoma. Two of them had familial cardiac myxoma complicated with Carney complex. The other five patients were characterized as sporadic cardiac myxomas. We analyzed the PRKAR1A gene of all patients by the polymerase chain reaction (PCR)-single-strand conformation method, followed with direct sequence analysis.

We identified a novel mutation (494delTG) in exon 4A of the PRKAR1A gene in the patients with Carney complex. A 16-year-old proband had a left atrial myxoma, pituitary adenoma and skin pigmentation. His father also had left atrial myxoma and skin pigmentation. In contrast, no mutations in the PRKAR1A gene were identified in the other five patients with sporadic cardiac myxomas.

These results suggest that mutation of the PRKAR1A gene may be associated with familial cardiac myxoma in Carney complex but may not be associated with sporadic cardiac myxoma.