Objective:To study the clinical features of transthyretin amyloid polyneuropathy (ATTR-PN) caused by Ser77Tyr mutation.Methods:The clinical data of a patient with ATTR-PN caused by Ser77Tyr mutation, admitted to our hospital from Department of Neurology, Mindong Hospital Affiliated to Fujian Medical University, were retrospectively analyzed. Literature on patients with ATTR-PN caused by Ser77Tyr mutation in Pubmed, Web of Science, CNKI and Wanfang databases and those with ATTR-PN caused by Val30Met mutation in Pubmed and Web of Science were searched and screened, and clinical characteristics of these patients were extracted. The differences of clinical characteristics among patients with ATTR-PN caused by Ser77Tyr or Val30Met mutations were compared.Results:(1) Transthyroxin ( TTR) gene Sanger sequencing results showed Ser77Tyr heterozygous pathogenic mutation; Congo red staining of biopsy sample in the patient 2.5 years after onset showed amyloid deposition. (2) Seventy-eight patients with ATTR-PN caused by Ser77Tyr mutation were summarized, they mostly had onset at 50-60 years old; male patients had higher incidence (74.4%); most patients (78.0%) had positive family history; most patients had sensory symptoms as initial symptom (72.0%), which gradually progressed to extensive peripheral nerve involvement and combined with widespread heart damage (96.4%) over several years; electrophysiological examination mainly showed axonal damage and carpal tunnel syndrome; the tissue biopsy had high positive rate(84.8%). (3) There were 192 and 96 patients with ATTR-PN caused by early-onset and late-onset Val30Met mutations, respectively; compared with patients with ATTR-PN caused by early-onset Val30Met mutation, patients with ATTR-PN caused by Ser77Tyr mutation had significantly higher incidence of deep sensory disturbance (28.6% vs. 58.5%, P<0.05). Compared with patients with ATTR-PN caused by late-onset Val30Met mutation, patients with ATTR-PN caused by Ser77Tyr mutation had increased incidence of mild sensory disturbance (56.3% vs. 75.0%) and decreased incidence of limb weakness (65.6% vs. 48.3%), with significant differences ( P<0.05). ATTR-PN patients caused by Ser77Tyr mutation had significantly higher incidence of carpal tunnel syndrome than ATTR-PN patients caused by early-onset and late-onset Val30Met mutations (75.4% vs. 10.8% and 25.0%) and significantly higher incidence of cardiac damage than ATTR-PN patients caused by early-onset Val30Met mutation (96.4% vs. 80.5%, P<0.05). Conclusion:Ser77Tyr mutation has some distinctive clinical features: relatively balanced damage of large and small fibers, prominent carpal tunnel syndrome, and obvious heart disease; early identification of these features and administration of tissue biopsy and gene detection are helpful for early diagnosis.