Congenital myasthenic syndrome 22 due to PREPL gene mutation in 2 patients: case report and literature review / 中华实用儿科临床杂志

ABSTRACT

Clinical data of two patients with congenital myasthenia syndrome type 22 (CMS22) treated at the Children′s Hospital of Fudan University from February 2019 to November 2021 were retrospectively analyzed, and relevant literatures were reviewed.Both patients were female, aged 3 months 18 days and 3 months 26 days, respectively, with typical clinical features of CMS (postnatal onset, skeletal muscle weakness, feeding difficulties, and delayed motor development). Genetic testing revealed that one patient had a homozygous frameshift mutation of the PREPL gene from maternal uniparental disomy c. 1282_1285del(p.F428fs*18), and the other one had a compound heterozygous mutation, including the paternal homozygous frameshift mutation of the PREPL gene and maternal monoallelic nonsense mutation and splicing mutation c. [1501G>T; 2020+ 1G>T], p.[G501*; -]. Two patients were treated with Pyridostigmine bromide at the age of 6 months old and 4 months old, respectively, and the medication last for 15 months and 3 months (still under treatment), respectively.The treatment was effective.Through literature review, 7 English language articles were retrieved, involving 13 cases (2 cases in the presented study were included). The main clinical symptoms of CMS22 included neonatal onset with feeding difficulties and motor development delay, accompanied by cognitive impairment, growth hormone deficiency, and obesity.Genetic testing is favorable to the early diagnosis, early treatment, and symptom relief.