A case with silent type of pseudo-acholinesterasemia

One case of pseudo-acholinestrasemia was experienced in our hospital. The patient was a 54-year-old female with sigmoid colon cancer. A preoperative examination showed that her cholinesterase (ChE) level was 7 IU/L (normal range: 3,700-5,400 IU/L) although no abnormalities were found in other enzymes derived from the liver, total protein and albumin level in the serum. An investigation of eight family members over two generations revealed two cases of acholinesterasemia in addition to the patient. Immunological examination by Ouchterlony's method and isoenzyme analysis by polyacrylamide gel electrophoresis showed that ChE production was absent in this case, while dibucaine or fluoride number was normal among the family members. Based on these results, it was concluded that this patient belonged to the silent type of homozygote. A case of pseudo-acholinesterasemia, which is very rare in Japan, is described.