[Clinical applications of molecular diagnosis of retinoblastoma ain 15 families].
OBJECTIVE
In 40% retinoblastoma (Rb) results from a hereditary mutation of the Rb susceptibility gene (RB1). In this study, we tested the usefulness of intragenic DNA analysis for ophthalmologic follow-up in affected families.


METHODS
Molecular analysis was performed on 103 DNA samples of 15 Rb families. We used 7 intragenic polymorphic markers and one within the ESD gene for mutation linkage analysis.


RESULTS
DNA analysis was informative in 88% of relatives at risk of developing Rb. Among them, the presence of a mutated RB1 allele was excluded in 46%, while 29% were unaffected carriers and 25% had inherited the Rb predisposition.


CONCLUSIONS
In the majority of familial Rb, the DNA analysis allows the identification of children carrying a RB1 mutation and who will need a close ophthalmologic follow-up under general anesthesia. When the mutated gene is absent, ophthalmological examination under narcosis is unnecessary. Finally, identification of asymptomatic carriers improve the accuracy of genetic counselling.
Lendi
B
B
Hôpital Ophtalmique Jules Gonin, Lausanne.
Pescia
G
G
Thonney
F
F
Balmer
A
A
Munier
F
F
D000328:Adult; D000483:Alleles; D002648:Child; D004252:DNA Mutational Analysis; D005134:Eye Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000517:prevention & control; D005260:Female; D006580:Genetic Carrier Screening; D005817:Genetic Counseling; D006801:Humans; D007223:Infant; D008297:Male; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D012175:Retinoblastoma / Q000175:diagnosis / Q000235:genetics* / Q000517:prevention & control; D012307:Risk Factors