Population and pharmacogenetic studies on serum cholinesterase (pseudocholinesterase) on a population of central Italy (Rome)

Cermele, Giovanni ; Santolamazza, Carlo ; Pulvirenti, Marisa ; Blandamura, Vincenzo ; Sanpietri, Elena ; Levi, Michele ; Pacifici, Laura E. ; Modiano, Guido

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 81 (1987) no. 1, pp. 77-85

Résumé

Serum cholinesterase or pseudocholinesterase (symbol: E, for Esterase), being able to hydrolyse succinyldicholine (SCC), a substance commonly used in the first stage of general anesthesia to induce muscle relaxation, is responsible for the normally short duration (3'-4') of the myorelaxation induced by SCC. The high sensitivity to SCC of subjects with on E activity displays itself as a more or less prolonged apnea following SCC administration that may cause serious clinical problems. The main cause of the low E activity of some subjects is the occurrence of a relatively common allele, the $E_{1}^{a}$, which has associated a low E activity so that the heterozygotes for $E_{1}^{a}$ and the normal allele have a moderately prolonged apnea following SCC administration and the $E_{1}^{a}$$E_{1}^{a}$ homozygotes' apnea lasts even for hours. Thus the estimate of the frequency of the $E_{1}^{a}$ allele is relevant from the clinical, besides of the anthropological, point of view. In the present paper an $E_{1}^{a}$ gene frequency estimate $= 0.011 \pm 0.004$ was arrived at by studying 403 subjects of the Rome population. This estimate was improved by pooling it with another one obtained with another random sample from the same popu- lation and became $= 0.011 \pm 0.002$. Besides and independently from these population studies, the relationship between the E activity and the duration of the SCC-induced muscle relaxation-described by Kalow and Genest long ago (1957)-was reexamined by a different approach. A highly significant negative correlation $(r = — 0.37; P 0.001)$ was found between these two variables showing that the E activity is one of the major factors upon which depends the SCC-induced myorelaxation time even in the range of the normal values of activity of this enzyme.