Objective Our purpose was to investigate the pathogenic gene mutation of a Han Chinese family with vitreous amyloidosis.Methods The 9 individuals(proband,1 affected member and 7 unaffected members) of the family were selected and their DNA was extracted from peripheral blood.The 4 exons of transthyretin(TTR) gene were amplified by polymerase chain reaction(PCR) technique.The amplified products of TTR gene were sequencing by Sanger technique.We also selected 100 unrelated healthy individual as the control group.Results By DNA sequencing,a heterozygous mutation was found in 4 of the 9 subjects from the family.The transition of adenine to cytosine(AAG ＞ ACG) was detectable in exon 2 of TTR,which changed the amino acid composition at codon 35 (Lys35Thr).This mutation did not presented in control group.Conclusion The heterozygosis mutation of TTR gene Lys35Thr should be a pathogenic mutation for the family with vitreous amyloidosis.

Objective　To analyze characteristics of video polysomnography （V-PSG） for different clinical phenotypes of sleep related rhythmic movement （SRRM）. Methods　The clinical data of patients with sleep related rhythmic movement diagnosed by video polysomnography（V-PSG） monitoring in our sleep center from December 2017 to August 2020 were analyzed retrospectively，their genders，ages，first episode time，clinical types and PSG results were statistically analyzed. Results　A total of 21 SSRM patients were performed in 959 sleep monitoring cases，including 16 males （76.2%） and 5 females （23.8%）. The mean age was 27.29±11.64 years old，and 17 cases were ≥18 years old. SSRM first occurred in 9 adults （42.9%），4 children （19%），4 patients （19.0%） with unclear onset age，and 4 patients （19.0%） with adolescent onset. The movement frequency of 21 cases （100%） was lower than 0.5 times per second. The clinical manifestations were head shaking type in 10 cases （47.6%），body shaking type in 1 case （4.8%） and mixed type in 10 cases （47.6%）. 14 cases occurred REM in SSRM cases （66.7%），NREM2 2 cases （9.5%%），NREM2+REM3 cases （14.3%），and awake 2 cases （9.5%）. PSG showed that the sleep efficiency of SSRM patients was decreased，the latency period of REM was prolonged and the total waking time after sleep was prolonged，and the total sleep time and sleep stage ratio were approximately normal. Hamilton anxiety score was greater than 8 in 12 cases （57.14%）. Conclusion　Adult SSRM is not uncommon，and it is mostly the first episode in adult life. In adults，SSRM is mainly manifested as head shaking type and mixed type，and the occurrence frequency of REM is the highest. The clinical significance of SSRM and its relationship with REM sleep need to be further studied and evaluated.

Objective : To analyze the morphology and incidence of middle mesial canal (MM) and isthmus in the mandibular first permanent molar by cone-beam computed tomography (CBCT). Methods: Statistical analysis was performed on images from patients who underwent CBCT examination in the Department of Radiology at Stomatological Hospital, Southern Medical University. Samples exhibiting root canal treatment, root resorption and calcification were excluded. Data regarding sex, age, the presence or absence of isthmus and MM, and the number of roots and root canals were recorded. Results : Of the 217 mandibular first molar samples, 8 (3.7%) had an MM, and 2 (0.9%) had an independent apical foramen. The overall incidence rate of isthmus was 57.1%; this rate was 50.7% in the cervical third of the root canal, 17.5% in the middle third, and 13.4% in the apical third. The incidence rate of isthmus was 61.8% on the left side, 52.3% on the right side, 58.7% in males, and 55.8% in females. No significant difference was found between the left and right sides or between females and males (P > 0.05). The incidence rate of isthmus in people under 60 was greater than 50% but was significantly lower in people older than 60. Conclusion Only a very small proportion of MMs have an independent apical foramen in the mandibular first molar. The incidence of isthmus in the mesial root of the mandibular first permanent molar is high, and isthmus usually occurs in the cervical third of the root canal. During root canal treatment or apical surgery, attention should be given to the physical and chemical preparation of the isthmus.