Author Correction: A functional Cis-eQTL locus in lncRNA ZNRD1-AS1 contributes to the susceptibility of endometrial cancer.

Correction to: European Review for Medical and Pharmacological Sciences 2019; 23 (18): 7802-7807-DOI: 10.26355/eurrev_201909_18989-PMID: 31599404, published online 15 September, 2020. The authors state that "to compare the results with those of bladder cancer in the literature we reported the study by Li D, Song L, Wen Z, Li X, Jie J, Wang Y, Peng L. Strong evidence for LncRNA ZNRD1-AS1, and its functional Cis- eQTL locus contributing more to the susceptibility of lung cancer. Oncotarget 2016; 7: 35813-35817. In particular, we referred to their table format, but we misused the reference table as the official table in the manuscript". In addition to Table I, the authors make the following corrections: • in the abstract results change "(OR: 1.33; 95% CI: 1.09-1.61; p = 0.004)" to "(OR: 1.31; 95% CI: 1.08-1.6; p=0.007)." • in the "Association of tagSNPs of the Cis-eQTL for ZNRD1 in ZNRD1-AS1 Gene Region With EC Susceptibility" paragraph change "(OR: 1.33; 95% CI: 1.09-1.61; p = 0.004)" to "(OR: 1.31; 95% CI: 1.08-1.6; p=0.007), "1.71 (95% CI: 1.11-2.64)" to "1.67 (95% CI: 1.07-2.59)", and "(0.004 × 3 = 0.012 < 0.05)" to "(0.007*3=0.021<0.05)". There are amendements to this paper.  The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/18989.

[Effects of intravenous methylprednisolone pulse therapy on recurrent optic neuritis associated with aquaporin 4 antibody seropositive neuromyelitis optica].

Objective: To observe the effects of intravenous methylprednisolone pulse (IVMP) therapy on the recovery of visual acuity and its influencing factors in patients with the relapse of aquaporin (AQP) 4 antibody positive neuromyelitis optica related optic neuritis (NMO-ON). Methods: Retrospective case series. Forty-eight eyes of 35 patients diagnosed as NMO-ON in the Neuro-ophthalmology Clinic of Beijing Tongren Hospital from September 2012 to April 2018 were included in this research. All patients were AQP4 antibody seropositive, and had clinical manifestations of acute optic neuritis, with a history of optic neuritis treated with glucocorticoids effectively. They received the treatment of IVMP 500 mg/d or 1 000 mg/d for 3 to 5 days. The post-treatment and pre-treatment visual acuities were compared. Improving four lines or more was considered as markedly effective, improving two or three lines as effective, and improving one line or no change or a decline as no effect. The impacts of age, visual acuity at onset, relapse rate and dosage on the acute exacerbation of NMO-ON were analyzed. Mann-Whitney U test and Kruskal-Wallis test were used for statistical analysis. Results: Among the 35 patients, there were 2 males and 33 females, aged from 15 to 73 years (median, 36 years). In the 48 eyes of recurrence, the treatment was effective 41.7% (20/48), effective 20.8% (10/48), and ineffective 37.5% (18/48). The IVMP therapy was effective in 25 of 34 eyes with one recurrence and 5 of 14 eyes with two or more recurrences, and the difference was statistically significant (Z=2.315, P=0.021). The efficacy in 13 eyes with preoperative visual acuity not lower than 0.05 (10/13) was better than 35 eyes with preoperative visual acuity lower than 0.05 (20/35), and the difference was statistically significant (Z=1.994, P=0.046). Different ages and doses (1 000 mg/d and 500 mg/d) made no significant difference in the efficacy (P=0.273,0.105). Conclusions: The IVMP therapy is effective for the NMO-ON relapse in patients who were AQP4 antibody seropositive. The effect of IVMP treatment at doses of 500 mg/d and 1 000 mg/d is similar. Furthermore, visual acuity less than 0.05 and more relapses reduce the efficacy in relapsed NMO-ON patients. (Chin J Ophthalmol, 2020, 56: 509-513).

A functional Cis-eQTL locus in lncRNA ZNRD1-AS1 contributes to the susceptibility of endometrial cancer.

OBJECTIVE: Endometrial cancer (EC) remains one of the most common gynecologic malignancies worldwide. However, the exact etiology is still unknown. Human Zinc ribbon domain containing 1 (ZNRD1) was involved in carcinogenesis and progression of multiple cancers, including EC. ZNRD1-AS1, a long noncoding RNA (lncRNA) located in the upstream of ZNRD1, has been reported as an essential component in carcinogenesis. However, the underlying relations of ZNRD1-AS1 with development of EC remain obscure. This study aims to evaluate the potential role of ZNRD1-AS1 and Cis-eQTL loci of ZNRD1 in the occurrence of EC. PATIENTS AND METHODS: We first evaluated the expression of ZNRD1-AS1 and ZNRD1 among EC tissues and corresponding normal tissues using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Then, to reveal the underlying mechanisms, we investigated the associations between Cis-eQTL loci of ZNRD1 in ZNRD1-AS1 and the susceptibility of EC. Further, in vitro experiments were conducted to evaluate the regulation role of rs9261204 on the expression of ZNRD1gene. RESULTS: Higher expression of ZNRD1-AS1 and lower expression of ZNRD1 were detected in the EC tissues, compared to the normal tissues. Minor allele of rs9261204 was significantly associated with increased risk of EC (OR: 1.31; 95% CI: 1.08-1.6; p=0.007) [corrected]. Furthermore, in vitro experiments confirmed that Ishikawa cells with rs9261204 G allele had lower mRNA level of ZNRD1, compared to the A allele. CONCLUSIONS: Our findings first showed the contribution of LncRNA ZNRD1-AS1 and Cis-eQTL loci of ZNRD1 to the development of EC. Further studies incorporating larger populations and functional assays are warranted.

[Effects of intravenous methylprednisolone pulse therapy on optic neuritis associated with AQP4 antibody seropositive neuromyelitis optica].

Objective: To observe the effect of intravenous methylprednisolone pulse (IVMP) therapy on the recovery of visual acuity and its influencing factors in patients with the first attack of optic neuritis associated with aquaporin-4(AQP4) antibody seropositive neuromyelitis optica. Methods: Retrospective case series study. A total of 165 eyes of 120 patients diagnosed as optic neuritis related to neuromyelitis optica for the first time in the Neuro-ophthalmology Clinic of Beijing Tongren Hospital from September 2012 to December 2017 were selected in this research. All patients had AQP4 antibody seropositivity and clinical manifestations of acute optic neuritis, excluding other diagnoses. All the patients received the treatment of IVMP 500 mg/d or 1 000 mg/d for 3 days, followed by a slowly tapering course of oral glucocorticoids. The post-treatment and pre-treatment visual acuities were compared. Improving four lines or more was considered as effective markedly, improving two or three lines as effective, and improving one line or no change or a decline as no effect. The onset age, visual acuity before treatment and doses in the acute exacerbation were analyzed. The Mann-Whitney U test and Kruskal-Wallis test were used for statistical analyses. Results: Among the 120 patients, there were 17 males and 103 females, with age ranging from 16 to 80 years (median, 44 years). There were 17.6% (29/165) of the eyes with conspicuous therapy, 33.3% (55/165) of the eyes with effective therapy and 49.1% (81/165) of the eyes with ineffective therapy. The effect of IVMP decreased obviously when the age of onset was over 50 years old [41.1%(23/56) vs. 56.0%(61/109), Z=2.645, P=0.008]. Patients with no light perception and light perception before treatment had better therapeutic effect than those with counting fingers-0.3 before treatment [72.2%(26/36), 72.7%(24/33) vs. 30.1%(25/83), Z=2.726, 2.967; P=0.006, 0.003]. Although the efficacy of patients with visual acuity of onset over 0.3 (9/13) was better than patients with counting fingers-0.3, but the difference was not statistically significant (Z=1.743, P=0.081). Different doses, including IVMP 1 000 mg/d and 500 mg/d, had no significant difference in the effect (Z=1.115, P=0.265). Conclusions: IVMP therapy is only valid for a half of eyes with optic neuritis associated with AQP4 antibody seropositive neuromyelitis optica. The effect of IVMP treatment at doses of 500 mg/d and 1 000 mg/d is similar. Furthermore, the visual acuity from finger counting to 0.3 and age of onset over 50 years old have an influence on the treatment effect. (Chin J Ophthalmol, 2019, 55: 180-185).

Morphological characteristics of P waves during selective pulmonary vein pacing.

OBJECTIVES: We sought to assess the value of 12-lead electrocardiogram (ECG) P-wave morphology to recognize the paced pulmonary vein (PV). BACKGROUND: Prediction of arrhythmogenic PVs producing ectopy or initiating atrial fibrillation (AF) using 12-lead ECG may facilitate curative ablation. METHODS: In 30 patients P-wave configurations were studied during sinus rhythm and during pacing at six sites from the four PVs: top and bottom of each superior PV and both inferior PVs. The P-wave amplitude, duration and morphology were assessed, and predictive accuracies were calculated for the most significant parameters. An algorithm predicting the paced PV was developed and prospectively evaluated in a different population of 20 patients. RESULTS; Three criteria were used to distinguish right from left PV: 1) a positive P-wave in lead aVL and the amplitude of P-wave in lead I > or =50 microV indicated right PV origin (specificity 100% and 97%, respectively); 2) a notched P-wave in lead II was a predictor of left PV origin (specificity 95%); and 3) the amplitude ratio of lead III/II and the duration of positivity in lead V(1) were also helpful in distinguishing left versus right PV origin. In addition, superior PVs could be distinguished from inferior according to the amplitude in lead II (> or =100 microV). In prospective evaluation, an algorithm based on the above four criteria identified 93% of left versus right PV and totally 79% of the specific PVs paced. CONCLUSIONS: Pacing from the different PVs produced a P-wave with distinctive characteristics that could be used as criteria in an algorithm to identify the PV of origin with an accuracy of 79%.

Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation.

BACKGROUND: Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulness and safety of irrigated-tip catheters in treating patients with APs resistant to conventional catheter ablation. METHODS AND RESULTS: Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%), 6 of which were located in the left free wall, 5 in the middle/posterior-septal space, and 7 inside the coronary sinus (CS) or its tributaries. Irrigated-tip catheter ablation was subsequently performed with temperature control mode (target temperature, 50 degrees C), a moderate saline flow rate (17 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) were successfully ablated with a median of 3 applications using irrigated-tip catheters. A significant increase in power delivery was achieved (20.3+/-11.5 versus 36.5+/-8.2 W; P:<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serious complications occurred. CONCLUSIONS: Irrigated-tip catheter ablation is safe and effective in eliminating AP conduction resistant to conventional catheters, irrespective of the location.

Left ventricular diastolic dysfunction in patients with so-called lone atrial fibrillation.

Lone atrial fibrillation (AF) is defined by the absence of identifiable causes of AF, but its hemodynamics have not been investigated. Twenty-eight patients with lone AF were compared with 14 control patients referred for Wolff-Parkinson-White ablation. Transthoracic and transesophageal echocardiography were performed to rule out structural heart disease, followed by transseptally performed complete hemodynamic evaluation of the left heart systolic and diastolic function. There was no evidence of diastolic dysfunction according to echocardiographic criteria in AF and control patients. There was no difference in echocardiographic measurements, except for a significantly higher inferosuperior left atrial dimension seen in the four-chamber apical view in AF patients (51+/-10 vs 40+/-6 mm, P = 0.03). Hemodynamic evaluation showed that end-diastolic left ventricular pressure and the nadir of the left atrial Y descent were significantly higher in lone AF patients versus controls: 13+/-5 versus 8+/-3 mmHg (P = 0.001) and 6.7+/-3 versus 4.6+/-2.7 mmHg (P = 0.05). Our results demonstrated the presence of diastolic left heart dysfunction in patients with so-called lone AF.

Mapping and ablation of left atrial flutters.

BACKGROUND: Typical right atrial isthmus-dependent flutters have been described in detail, but very little is known about left atrial (LA) flutters. METHODS AND RESULTS: We performed conventional and 3D mapping of the LA for 22 patients with atypical flutters. Complete maps in 17 patients demonstrated macroreentrant circuits (n=15) with 1 to 3 loops rotating around the mitral annulus, the pulmonary veins, and a zone of block or a silent area. In 2 patients, a small reentry circuit with a zone of markedly slow conduction was identified. Linear ablation performed across the most accessible part of the circuit cured 16 patients (73%) with a follow-up of 15+/-7 months. CONCLUSIONS: LA reentrant tachycardias are related to individually varying circuits and are amenable to mapping guided radiofrequency ablation.

Tracking dynamic conduction recovery across the cavotricuspid isthmus.

OBJECTIVES: We sought to assess the dynamic temporal course of conduction recovery during and after radiofrequency (RF) catheter ablation of the cavotricuspid isthmus. BACKGROUND: Although cavotricuspid isthmus block is accepted as the best end point of ablation for typical flutter, conduction recovery is thought to underlie many eventual recurrences. Its time course and frequency have not been determined. METHODS: In a prospective group of 30 patients (26 men and 4 women, age 64 +/- 12 years) undergoing ablation of typical flutter in the cavotricuspid isthmus, the morphology of the P wave during pacing from the low lateral right atrium after achievement of complete isthmus block was identified as a reference. Regression of this morphologic P wave change was confirmed to be associated with intracardiac evidence of the recovery of cavotricuspid isthmus conduction and was observed throughout the procedure both during ablation in sinus rhythm (n = 15, group B) and just after flutter termination (n = 15, group A). RESULTS: Stable complete isthmus block was achieved in all patients; 29 had a terminal positivity of the paced P wave. Flutter termination resulted in stable block and terminal P wave positivity in three patients, transient terminal P wave positivity and transient block despite continuing RF at the same site in five patients and no block in the remaining seven patients. Conduction recovery identified by recovery of P wave changes was nearly as common (48%) during ablation in sinus rhythm. Multiple recoveries were noted in some patients, and 72% of all recoveries occurred within 1 min. Conduction recovery was only rarely associated with coagulum, impedance elevation or pops. CONCLUSIONS: Conduction recovery in the cavotricuspid isthmus is common during and after ablation and can be accurately, dynamically and continuously observed by monitoring the recovery of the low lateral right atrial paced P wave change.

Catheter ablation for atrial fibrillation.

Atrial fibrillation is frequently disabling and resistant to antiarrhythmic drugs. Curative treatment by catheter-based ablation has been shown to be feasible either by achieving long linear lesions, mainly in the left atrium, or by targeting the initiating focus, most frequently in the pulmonary veins. This paper reviews the different ablation approaches, their results, potential complications, and relative merits.

Catheter ablation of chronic atrial fibrillation targeting the reinitiating triggers.

INTRODUCTION: We assessed the mode of reinitiation of atrial fibrillation (AF) after cardioversion and the efficacy of ablating these foci of reinitiation in patients with chronic AF. METHODS AND RESULTS: Fifteen patients, 7 with structural heart disease, underwent mapping and catheter ablation of drug-resistant AF documented to be persistent for 5 +/- 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowed mapping of the reinitiating trigger or the source of ectopy. Radiofrequency (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50 degrees C and a power limit of 30 to 40 W, with the endpoint being interruption of all local muscle conduction. A total of 32 arrhythmogenic PVs and 2 atrial foci (left septum and left appendage) were identified: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by abolition of PV potentials in 8, but potentials persisted in 6. A single ablation session was performed in 7 patients and 8 underwent two or three sessions because of recurrence of AF; ablation was directed at the same source due to recovery of local PV potential or at a different PV. No PV stenosis was noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 +/- 8 months. Anticoagulants were interrupted in 7 patients. CONCLUSION: PVs are the dominant triggers reinitiating chronic AF in this patient population. Elimination of PV potentials by ostial RF applications results in stable sinus rhythm in 60%. A larger group and longer follow-up are needed to investigate further the role of trigger ablation in curative therapy for chronic AF.

Electrophysiological end point for catheter ablation of atrial fibrillation initiated from multiple pulmonary venous foci.

BACKGROUND: The end point for catheter ablation of pulmonary vein (PV) foci initiating atrial fibrillation (AF) has not been determined. METHODS AND RESULTS: Ninety patients underwent mapping during spontaneous or induced ectopy and/or AF initiation. Ostial PV ablation was performed by use of angiograms to precisely define targeted sites. Success defined by elimination of AF without drugs was correlated with the procedural end point of the abolition of distal PV potentials. A total of 197 arrhythmogenic PV foci (97%)-single in 31% and multiple in 69%-and 6 atrial foci were identified. A discrete radiofrequency (RF) application eliminated the PV potentials in 9 PV foci, whereas 2 foci from the same PV required RF applications at separate sites in 19 cases. In others, a wider region was targeted with progressive elimination of ectopy. In 49 patients, multiple sessions were necessary owing to recurrent or new ectopy. The clinical success rates were 93%, 73%, and 55% in patients with 1, 2, and > or =3 arrhythmogenic PV foci. Recovery of local PV potential and the inability to abolish it were significantly associated with AF recurrences (90% success rate with versus 55% without PV potential abolition). PV stenosis was noted acutely in 5 of 6 cases, remained unchanged at restudy, and was associated with RF power >45 W. CONCLUSIONS: Multiple PV foci are involved in initiation of AF, and elimination of PV muscle conduction is associated with clinical success.

Dual-loop intra-atrial reentry in humans.

BACKGROUND: Dual-loop atrial reentrant tachycardias have not been clinically described. METHODS AND RESULTS: Five patients (3 men, 2 women; mean age, 48+/-16 years) were studied 24+/-15 years after surgical closure of an ostium secundum atrial septal defect for drug-resistant atrial tachycardia. Complete tachycardia mapping was performed in the right atrium with multipolar catheters and a 3-dimensional electroanatomic mapping system (Biosense), followed by linear radiofrequency ablation of the narrowest part of each complete loop. Six tachycardias with a typical flutter morphology, a cycle length of 262+/-40 ms, and a superior f-wave axis (-77+/-11 degrees ) were mapped, 4 with a Biosense map including 106+/-32 points. Five figure-8 tachycardias had a counterclockwise loop around the tricuspid valve sharing a common anterior channel with a clockwise loop around the lateral atriotomy scar. One tachycardia was thought to have 2 counterclockwise loops around the same obstacles. Radiofrequency delivery in the cavotricuspid isthmus in each case transformed the tachycardia without any pause in a different morphology tachycardia with an inferior P-wave axis (50+/-42 degrees ) and nearly the same cycle length (272+/-39 ms) but with the periatriotomy loop alone. This arrhythmia required ablation of a second isthmus: between the lower end of the atriotomy and the inferior vena cava in 4 and the superior tricuspid annulus in 1. After a follow-up of 19+/-6 months, there were no recurrences. CONCLUSIONS: Figure-8 double-loop tachycardias mimicking the ECG pattern of a common atrial flutter occur in some patients after a surgical atriotomy. Ablation of 1 loop produces a sudden transformation to a new reentrant tachycardia formed of the remaining loop that requires ablation at a second isthmus.

Multiple sources initiating atrial fibrillation from a single pulmonary vein identified by a circumferential catheter.

The pulmonary veins are the predominant source of ectopic activity initiating AF. The reproducibility of intrapulmonary vein activation during ectopic activity and/or initiation of multiple AF episodes was examined. Eighty-nine pulmonary veins (PVs) among 29 patients undergoing radiofrequency ablation of AF were studied with a 15- to 20-mm diameter, circumferential PV catheter equipped with ten electrodes and a deflectable shaft. Local electrograms were recorded simultaneously during sinus rhythm, ectopic activity, or AF onset, spontaneously or induced via the catheter left in a stable position. Fifty-four arrhythmogenic veins were identified, 39 showing isolated ectopy, and 8 displayed repetitive ectopy (in salvos). The earliest site of activation and the sequence of intra-PV activation during isolated ectopy was identical to that observed during consecutive ectopic complexes in 77% and variable in 23% during isolated ectopy. The earliest activity was sometimes limited to a single bipole. During repetitive ectopy and AF initiation, multiple sources and/or variable activation patterns were noted in 53% of instances, indicating the presence of multiple arrhythmogenic foci within the same PV. Simultaneous electrogram recordings with a circumferential PV catheter identified the presence of multiple arrhythmogenic foci within a single PV.

Concealed left pulmonary vein potentials unmasked by left atrial stimulation.

Pulmonary vein potentials (PVPs), though obvious during ectopic activity, are frequently invisible during sinus rhythm when they need to be distinguished from left atrial (LA) potentials to perform successful ablation procedures. Thirty-six patients with paroxysmal atrial fibrillation underwent circumferential PV mapping with a circular ten-electrode catheter during sinus rhythm, and during pacing from the right atrium, proximal and distal coronary sinus (CS), and LA. Ablation was performed at the ostium of the PV, the procedural endpoint consisting of electrical disconnection of the PV from the LA. A total of 93 PVs (excluding the right inferior PV) were mapped. During sinus rhythm, distinct right PVPs were present in all instances, while they were concealed within the electrograms recorded from the left inferior and superior PV in 23 (64%) patients. Distal CS or LA appendage pacing unmasked and separated left PV from LA potentials by a mean of 19 +/- 14 ms; the LA-to-left-PV potential interval measured 36 +/- 14 ms. The number of deflections also increased from 2.1 +/- 0.7 during sinus rhythm to 3 +/- 1.4 during LA stimulation. However, in the right superior PV, pacing caused overlapping of atrial potentials with right superior PVPs. RF ablation of the left PVPs was performed during distal or LA pacing in 23 patients, while in the right superior PV it was performed during sinus rhythm eliminating all, including unmasked, left PVPs, providing proof of their PV origin. Distal CS or LA pacing is required to recognize left PVPs in approximately 2/3 of patients and facilitates RF ablation.

HLA-encoded susceptibility to insulin-dependent diabetes mellitus is determined by DR and DQ genes as well as their linkage disequilibria in a Chinese population.

HLA-DRB1 and -DQB1 genes were analyzed in 98 Chinese IDDM patients and 205 control subjects from Taiwan. The DRB1*0301-DQB1*0201 haplotype conferred strong susceptibility (RR = 7.7, pc < 10(-5)). DRB1*0405 also conferred susceptibility (RR = 3.1, Pc < 0.0005) whereas DRB1*0403 (RR = 0.7) and DRB1*0406 (RR = 0.2) conferred protection. Indeed, the relative risk for the DRB1*0405-DQB1*0302 haplotype (RR = 33.7, Pc < 0.002) was 48 and 168 times higher than those conferred by the DRB1*0403-DQB1*0302 and DRB1*0406-DQB1*0302 haplotypes, respectively, suggesting that the protection conferred by DRB1*0403 and 0406 is dominant over DQB1*0302. The strong linkage disequilibrium observed between DQB1*0302 and DRB1*0403(0406) can thus explain the surprising finding that the frequency of DQB1*0302 was not significantly increased in the Chinese IDDM patients (RR = 0.9). Because the DRB1*0405-DQB1*0302 haplotype (RR = 33.7) conferred higher susceptibility than the DRB1*0405-DQB1*0401 (RR = 2.5) or DRB1*0405-DQB1*0301 (RR = 2.1) haplotypes, DQB1*0302 is indeed a susceptibility factor, while both DQB1*0301 and DQB1*0401 may confer protection against IDDM. The increased frequency of the protective DQB1*0401 allele in patients compared to controls is due to linkage disequilibrium between DRB1*0405 and DQB1*0401. Interestingly, the previously demonstrated protective effect of DQB1*0602 was not very strong in the Chinese (RR = 0.4). Our results suggested that HLA-encoded susceptibility to IDDM is determined by the combined effects of all DR and DQ molecules present in an individual. Therefore, the genotypic combinations of DR and DQ genes as well as their linkage disequilibria can influence IDDM susceptibility. At least four DR and DQ molecules conferring high susceptibility (DRB1*0301, DRB1*0405, and DQ alpha/beta 0301/0201 and 0301/0302) occur at high frequency in the Chinese population. However, linkage disequilibria between highly susceptible DR and protective DQ or vice versa (e.g., DRB1*0405-DQB1*0301[0401] and DRB1*0403[0406]-DQB1*0302) are probably responsible for the lower incidence of IDDM in the Chinese.