Karyotyping in retinoblastoma--a statistical approach.
OBJECTIVE
Karyotype analysis in hereditary retinoblastoma is considered to be of marginal value in risk prediction due to uncertainties in the assessment of 13q14 deletions. However, it is a low cost genetic test for retinoblastoma in developing countries. In the present study, the results of karyotype analysis were refined by a statistical method to overcome limitations.


METHODS
Karyotype analysis was performed by trypsin-Giemsa banding and naked eye karyotyping for 33 bilateral, 25 unilateral and one regressed retinoblastoma patients. The percentage of metaphases with 13q14 deletions in each case was plotted on a scatter diagram. Normalization of the data was achieved by log transformation and the results were statistically analyzed by one-sample 't' test using SPSS version 9.0.


RESULTS
Seven samples had 13q14 deletion percentages above the cutoff value. One-sample 't' test showed significance (p< 0.001). By this method, two unilateral and five bilateral patients had 13q14 deletions, constituting 11.8 % of cases.


CONCLUSIONS
For accuracy, statistical analysis should be considered as an adjunct in karyotyping.
Joseph
Biju
B
SNONGC Dept of Genetics and Molecular Biology, Medical Research Foundation, Chennai 600 006, Tamil Nadu, India.
Paul
Pradeep G
PG
Elamparithi
Anuradha
A
Roy
Joseph
J
Vidhya
Authiappan
A
Shanmugam
Mahesh P
MP
Kumaramanickavel
Govindasamy
G
D002871:Chromosome Banding; D002872:Chromosome Deletion; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics*; D006801:Humans; D007621:Karyotyping / Q000379:methods*; D019572:Retinal Neoplasms / Q000235:genetics*; D012175:Retinoblastoma / Q000235:genetics*; D013223:Statistics as Topic