Sex mutation ratio in retinoblastoma and retinoma: relevance to genetic counseling.
OBJECTIVE
The parental origin of initial somatic and germline mutations (M1) in the retinoblastoma gene (RB1) was explored in 36 retinoblastoma (Rb) and 5 retinoma patients, of which 16 were presumably non-hereditary and 25 were hereditary. By this approach the male:female mutation ratio was determined by the gender quotient of mutation origin.


RESULTS
The male to female mutation ratio in hereditary Rb was 19:2, which is consistent with a significant bias towards paternal origin of germline mutation. This ratio was of 5:2 in non-hereditary Rb which is not significant.


CONCLUSIONS
Together with the published data, these results support a preferential paternal mutagenesis in hereditary Rb, but appear to reject paternal genomic imprinting at the RB1 locus as previously proposed in non-hereditary Rb. Genetic counseling in sporadic Rb may be substantially improved by the identification of the parental origin of initial mutation.
Munier
F L
FL
Hôpital Ophtalmique Jules Gonin, Lausanne.
Thonney
F
F
Balmer
A
A
Héon
E
E
Pescia
G
G
Schorderet
D F
DF
D015331:Cohort Studies; D005134:Eye Neoplasms / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D016161:Genes, Retinoblastoma / Q000235:genetics; D006580:Genetic Carrier Screening; D005817:Genetic Counseling; D018095:Germ-Line Mutation / Q000235:genetics*; D006801:Humans; D008297:Male; D010375:Pedigree; D012175:Retinoblastoma / Q000175:diagnosis / Q000235:genetics*; D012729:Sex Chromosome Aberrations / Q000175:diagnosis / Q000235:genetics*