A Case Report of Primary Neonatal Hypocholinesterase Caused by Homozygous Frameshift Mutation of the utyrylcholinesterase (BCHE) Gene and Review of Literature.

Background: Primary neonatal hypocholinesterase is rare; its genetic pattern and mutation still need to be further studied.

Methods: The patient and his parents are studied using next-generation sequencing technology.

Results: A boy one day after birth is admitted to the Neonatal Intensive Care Unit at our hospital after experiencing intermittent vomiting for 12 hours. The patient's serum cholinesterase level (113 - 283 U/L) is lower than normal value (4,000 - 12,600 U/L). Many factors of low serum cholinesterase are excluded. We highly suspect that it may be related to congenital factors. Molecular genetic test results show that the patient carried the BCHE gene (NM_000055.2) and has homozygous frameshift mutations at exon 2 c.401dupA (p.Asn134fs) of chromosome 3q26. It is a pathogenicity mutation. This locus mutation belongs to a novel pathogenic mutation. As a result of this mutation, the 134th amino acid Asn began to frameshift and the translation is terminated early. It can cause the Encoding of protein to truncate and lose its normal function. His parents' serum cholinesterase levels (father: 5,135 U/L; mother: 4,367 U/L) are in the normal value range, but his parents carried a heterozygous BCHE gene.

Conclusions: This study suggests that gene sequence detection should be carried out early in hypocholinesterase of nknown cause in neonates. This study can not only improve understanding of the etiology and pathological mechanism of hypocholinesterase, but also it can enlarge the hypocholinesterase gene mutation spectrum.