Familial hypocholinesterasemia found in a family and a new confirmed mutation

A 45-year-old man was hospitalized because of acute hepatitis. His serum cholinesterase (ChE) was below 10 IU/l (normal range: 105-240 IU/l) during the disease course and after his recovery. The patient was suspected of having familial hypocholinesterasemia. His family members were healthy except that his father had hypertension and gall stones. Analysis of ChE gene in the propositus and his family revealed three point mutations at nucleotides 298 (CCA to TCA), 1,410 (CGT to CGG) and 1,615 (GCA to ACA). The first mutation caused an amino acid change at codon 100 from proline to serine, which was a new mutation not previously reported, but the second one was a silent mutation. The third mutation resulted in an amino acid alteration from alanine to threonine at codon 539 in exon 4 of the ChE gene. The mode of transmission of these mutations is described.