Single coronary artery anomaly: the left main coronary artery originating from the proximal segment of right coronary artery.

This case report we presented is that the anomalous left main coronary artery (LMCA) originates from the proximal segment of right coronary artery. In order to confirm the origin and course of the anomalous LMCA, a multi-slice computed tomography (MSCT) of the heart was performed on a 64-slice machine (Philips 64 Slice, Philips, USA) after 6 months of coronary angiography operation. The results showed that the anomalous LMCA originates from the proximal segment of right coronary artery, lies posteriorly to the aorta before taking acute sharply to go between the aorta and left atrium. It was classified as R-II P subtype according to Lipton's classification. It is a rare case in the clinical practice.

[Novel mutations of potassium channel KCNQ1 S145L and KCNH2 Y475C genes in Chinese pedigrees of long QT syndrome].

OBJECTIVE: Hereditary long QT syndrome (LQTS) is a cardiac disorder characterized by prolongation of QT interval on electrocardiograms (ECGs) and syncope and sudden death caused by a specific multi-polymorphic ventricular tachyarrhythmia known as torsade de pointes. LQTS is caused by mutations in cardiac sodium channel gene SCN5A; potassium channel subunit genes KCNQ1, KCNH2, KCNE1, KCNE2, KCNJ2; calcium channel gene Cav2.1. and ankyrin-B gene ANK2. METHODS: We characterized 77 Chinese LQTS patients with clinical manifestations and mutations in the main LQTS genes, KCNQ1 and KCNH2 using PCR and sequence analysis. RESULTS: The spectrum of ST-T-wave patterns of 24 (31.2%) probands were considered as LQT1, 42 (54.5%) as LQT2 and 3 (3.9%) as LQT3. The remaining 8 (10.3%) could not be characterized. The average age for this population of LQTS patients was (27.6 +/- 16.4) years and the average QTc (561 +/- 70) ms, and the age of the first syncopal attack was (17.6 +/- 14.7) years. The triggering factors for cardiac events happening in these mutation carriers included physical exercise, emotional excitement and auditory irritation. We identified 4 KCNQ1 mutations and 7 KCNH2 mutations. Six of them were first identified with some data already shown. In this paper we showed the data of 6 other mutations. CONCLUSIONS: LQT2 is the most common type of LQTS in Chinese; 2 mutations of KCNQ1 and KCNH2 were first identified in this report; there are some differences between Chinese and North American or European LQTS patients in clinical characters and ECG.

[Heterozygous mutation in KCNQ1 cause Jervell and Lange-Nielsen syndrome].

OBJECTIVE: Jervell and Lange-Nielsen syndrome (JLNS) is a severe cardioauditory syndrome manifested as QT interval prolongation, abnormal T waves, and relative bradycardia ventricular tachyarrhythmias. In this report, we screened a nonconsanguineous families with JLNS for mutations in KCNQ1. METHODS: Mutation analysis was performed by using purified PCR products to direct sequence analysis on an ABI-3730XL automated DNA sequencer. The whole sequence of proband' KCNQ1 was screened firstly, then screened the mutation exon sequences of others of the family and 50 unrelated normal persons. RESULTS: A heterogeneous mutation was identified in the patients of the JLNS family, a missense mutation (G-->T) at nucleotide 917 encoded in exon 6 of KCNQ1. This substitution leads to a change from glycine to Valine at codon 306(G306V) corresponding to the S5 transmembrane segment of KCNQ1. The other normal members of the family and 50 unrelated normal persons were not identified this mutation. CONCLUSION: The result suggested that not only homozygous mutations or compound heterozygous mutations in KCNQ1 could cause Jervell-Lange-Nielsen syndrome, the single heterozygous mutation may also cause Jervell-Lange-Nielsen syndrome.

[The mutation scanning of KCNQ1 gene for 31 long QT syndrome families].

OBJECTIVE: To search for the mutations of potassium voltage-gated channel, KQT-like subfamily member 1(KCNQ1) gene in 31 Chinese long QT syndrome(LQTS) families. METHODS: Due to the genetic heterogeneity, the genotype of patients was first predicted based on the spectrum of ST-T-wave patterns on ECG. Ten of 31 probands were considered as LQT1. Then the mutation of KCNQ1 gene was screened by the polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) technique combined with DNA sequencing in all members of these 10 families. To avoid omitting some LQT1 patients without typical characteristics and also to do methodological comparison, the mutations of KCNQ1 gene on 16 exons were screened by PCR and direct DNA sequencing in the rest 21 non-LQT1 probands only. Co-segregation analysis was carried out after the finding of an abnormal sequence. In case that the abnormality existed in patients only, the test of such exon was performed in 50 irrelevant normal individuals. RESULTS: Two missense mutations and three single nucleotide polymorphisms (SNPs) were found in the LQT1 predicted families. The two mutations were S277L (1 family) and G306V (1 family) in exon 5 and were not reported previously. Three polymorphisms were 435C-->T (7 families), 1632C-->A (1 family), and IVS1+9 C-->G (3 families). Only a splice mutation IVS1+5G-->A (2 families) and a polymorphism IVS10+18C-->T (1 family) were found in the non-LQT1 predicted probands. All three mutations were localized within the functional domain of KCNQ1 and were co-segregated with the disease, and were not found in 50 normal individuals. CONCLUSION: Two novel missense mutations, 1 splice mutation and four SNPs on KCNQ1 gene were found in the 31 LQTS families. Combined with ECG-based genotype prediction, PCR-SSCP could find most mutations on KCNQ1 and be a simple and economic method for screening LQTS.

[Spectrum of ST-T-wave changes in hereditary long-QT syndrome in Chinese].

OBJECTIVE: To evaluate the spectrum of ST-T-wave patterns in Chinese patients with hereditary long-QT syndrome. METHODS: ECGs of 61 families were studied to determine ST-T-wave patterns. Genotypes were identified by sequencing. RESULTS: 32 cases showed similarity to LQT1, 41 to LQT2 and 2 to LQT3 in ECG, and 3 cases could not be classified. QTc of the patients with symptom was (0.547 +/- 0.08) sec and that of the patients without symptoms was (0.526 +/- 0.06) sec, both were much longer than that of normal members of the families. T wave patterns were different in 48 cases at different time. QTc difference in a same person between two times or DeltaQTc were as follows: (0.048 +/- 0.057) sec in patients and (0.023 +/- 0.017) sec in normal members (P < 0.001). 12 cases of LQT1 and 11 cases of LQT2 were identified by genotype sequencing. CONCLUSIONS: There are some differences in ST-T waves between these Chinese hereditary long-QT syndrome patients and European and American patterns. These patients showed greater variability in ST-T wave pattern including the changes in the same type, in the same pedigree and in the same patients at different time.