p.T315NfsX7 Thr315fsTer7 c.1020_1021InsA codon 315 ACC->AACC (p.T343NfsX7 Thr343fsTer7 in the primary sequence with the 28 amino-acids signal peptide) Silent variant rs754214624
BACKGROUND: Butyrylcholinesterase (BCHE) deficiency is characterized by prolonged apnea after the use of certain muscle relaxants with the genetic defect lying in the BCHE gene. METHODS: Two Chinese patients with no serum BCHE activity were studied. The BCHE genes were screened for mutations by polymerase chain reaction and direct DNA sequencing. RESULTS: Of the four mutations detected, two novel mutations were identified in the two patients, i.e., F474L, and an insertion of an adenine between nucleotide positions 395 and 396. This information was used to screen the immediate families of the patients for carrier status. CONCLUSIONS: We established the molecular basis of butyrylcholinesterase deficiency in two Chinese patients. The developed mutation detection assay provides a reliable method for identifying mutant BCHE carriers.
A family with serum cholinesterase (SChE) deficiency is reported. A 64-year-old woman was admitted for the excision of colon adenoma; her laboratory data revealed a markedly decreased level of SChE. SChE genes of the patient and her family members were amplified by the polymerase chain reaction (PCR) and analyzed by direct sequencing. The patient's SChE gene had a homozygous frame shift mutation, in which an extra adenine was inserted in codon 315 (ACC-->AACC), resulting in the appearance of a new stop codon in codon 322. The family study disclosed that her brother and sister had the same frame shift mutations in homozygote and heterozygote, respectively.
Two different gene mutations associated with the silent phenotype for human serum cholinesterase were demonstrated. DNA from five individuals with silent gene phenotype of three unrelated Japanese families was amplified by the polymerase chain reaction (PCR) and analyzed by direct sequencing. The first instance demonstrated a G----C transversion at codon 365 from GGA (Gly) to CGA (Arg), which was seen in three individuals of the two families. This mutation was resulted to create a new Taq 1 restriction site (TCGA). The second mutation was shown by a double heterozygous condition with two different silent gene mutations in two members of remaining one family. These mutations were as follows: 1) one type was a frameshift mutation, in which an extra A was inserted in codon 315 (ACC----AACC) to create a new stop codon at position 322 and 2) the other was the same point mutation at codon 365 as seen in the first instance. These results indicated that many silent variants can be distinguished by direct sequence analyses of genomic DNA.
        
Title: Heterogeneity of the Silent Phenotype of Human Butyrylcholinesterase - Identification of Eight New Mutations Primo-Parmo SL, Bartels CF Ref: In Multidisciplinary approaches to cholinesterase functions - Proceedings of Fourth International Meeting on Cholinesterases, (Shafferman, A. and Velan, B., Eds) Plenum Press, New York:61, 1992 : PubMed