A HEMIZYGOTIC A-BASE TO CC-BASE CHANGE OF THE CHM GENE CAUSING CHOROIDEREMIA ASSOCIATED WITH PINEALOMA

Background: Although mutations of the CHM gene have been reported in t he Caucasian patients with choroideremia, there have been no such repo rts in non-Caucasian patients. We analyzed the CHM gene in a Japanese patient with choroideremia associated with pinealoma. Methods: The met hod for screening was a nonradioisotopic modification of single-strand conformation polymorphism (SSCP) analysis. The PCR products from the patient and the carrier were screened and directly sequenced using an automated DNA sequencer. The PCR product of the carrier was also subcl oned into a vector and the subcloned products were sequenced. Results: SSCP analysis showed an identical abnormal band shift in the patient and the carrier. Direct sequence analysis showed a hemizygous A to CC mutation at nucleotide 1608 of the CHM gene in the patient, suspected to result in the absence or truncation of the predicted CHM protein. T he sequence using both the PCR product and the subcloned DNA of the ca rrier showed both wild-type and mutant bands indicating a heterozygote . Conclusion: The hemizygous mutation was detected in a patient and th e heterozygous pattern in his mother, the carrier, suggesting that thi s mutation caused the disease.