An Intron 9 CYP19 Gene Variant (IVS9+5G>A), Present in an Aromatase-Deficient Girl, Affects Normal Splicing and Is Also Present in Normal Human Steroidogenic Tissues.
OBJECTIVE
Splicing CYP19 gene variants causing aromatase deficiency in 46,XX disorder of sexual development (DSD) patients have been reported in a few cases. A misbalance between normal and aberrant splicing variants was proposed to explain spontaneous pubertal breast development but an incomplete sex maturation progress. The aim of this study was to functionally characterize a novel CYP19A1 intronic homozygote mutation (IVS9+5G>A) in a 46,XX DSD girl presenting spontaneous breast development and primary amenorrhea, and to evaluate similar splicing variant expression in normal steroidogenic tissues.


METHODS
Genomic DNA analysis, splicing prediction programs, splicing assays, and in vitro protein expression and enzyme activity analyses were carried out. CYP19A1 mRNA expression in human steroidogenic tissues was also studied.


RESULTS
A novel IVS9+5G>A homozygote mutation was found. In silico analysis predicts the disappearance of the splicing donor site in intron 9, confirmed by patient peripheral leukocyte cP450arom and in vitro studies. Protein analysis showed a shorter and inactive protein. The intron 9 transcript variant was also found in human steroidogenic tissues.


CONCLUSIONS
The mutation IVS9+5G>A generates a splicing variant that includes intron 9 which is also present in normal human steroidogenic tissues, suggesting that a misbalance between normal and aberrant splicing variants might occur in target tissues, explaining the clinical phenotype in the affected patient.
Endocrinology Service, Hospital de Pediatrx00ED;a Garrahan, Buenos Aires, Argentina.
Nora
N
Saraco
Suzana
S
Nesi-Franca
Romina
R
Sainz
Roxana
R
Marino
Rosana
R
Marques-Pereira
Julia
J
La Pastina
Natalia
N
Perez Garrido
Romolo
R
Sandrini
Marco Aurelio
MA
Rivarola
Luiz
L
de Lacerda
Alicia
A
Belgorosky
D000293:Adolescent; D000311:Adrenal Glands / Q000378:metabolism; D000568:Amenorrhea / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D009154:Mutation; D010641:Phenotype; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D019154:Protein Splicing; D013737:Testis / Q000378:metabolism
D001141:Aromatase; C561410:CYP19A1 protein, human