Clinical Characteristics of 5 Chinese LQTS Families and Phenotype-genotype Correlation

Summary: In order to assess the clinical manifestations and electrocardiogram (ECG) characteristics of Chinese long QT syndrome (LQTS) patients and describe the phenotype-genotype correlation, the subjects from 5 congenital LQTS families underwent clinical detailed examination including resting body surface ECG. QT interval and transmural dispersion of repolarization (TDR) were manually measured. Five families were genotyped by linkage analysis (polymerase chain reacting-short tandem repeat, PCR-STR). The phenotype-genotype correlation was analyzed. Four families were LQT2, 1 family was LQT3. Twenty-eight gene carriers were (14 males and 14 females) identified from 5 families. The mean QTc and TDRc were 0.56±0.04 s (range 0.42 to 0.63) and 0.16±0.04 s (range 0.09 to 0.24) respectively. 35.7 % (10/28) had normal to borderline QTc (≤ 0.460 s). There was significant difference in QTc and TDRc between the patients with symptomatic LQTS and those with asymptomatic LQTS, and there was significant difference in TDRc between the asymptomatic patients and normal people also. A history of cardiac events was present in 50 % (14/28), including 9 with syncope, 2 with sudden death (SD) and occurred in the absence of β-blocker. Three SDs occurred prior to the diagnosis of LQTS and had no ECG record. Two out of 5 SDs (40 %) occurred as the first symptom. Typical LQT2 T wave pattern were found in 40 % (6/15) of all affected members. The appearing-normal T wave was found in one LQT3 family. Low penetrance of QTc and symptoms resulted in diagnostic challenge. ECG patterns and repolarization parameters may be used to predict the genotype in most families. Genetic test is very important for identification of gene carriers.

Clinical and molecular characterization of 10 Chinese children with congenital adrenal hyperplasia due to 11beta‑hydroxylase deficiency

Background The clinical manifestations of nonclassical 11beta-hydroxylase deficiency are very similar to those of nonclassical 21-hydroxylase deficiency.For this study,we investigated the relationship between the clinical and molecular features of congenital adrenal hyperplasia caused by 11beta-hydroxylase deficiency and reviewed the related literature,which are expected to provide assistance for the clinical diagnosis and analysis of congenital adrenal hyperplasia.Methods Clinical data for 10 Chinese patients diagnosed with congenital adrenal hyperplasia in our hospital from 2018 to 2022 were retrospectively analyzed.We examined the effects of gene mutations on protease activity and constructed threedimensional structure prediction models of proteins.Results We describe 10 patients with 11beta-hydroxylase gene mutations(n=5,46,XY;n=5,46,XX),with 10 novel mutations were reported.Female patients received treatment at an early stage,with an average age of 2.08±1.66 years,whereas male patients received treatment significantly later,at an average age of 9.77±3.62 years.The most common CYP11B1 pathogenic variant in the Chinese population was found to be c.1360C>T.All mutations lead to spatial conformational changes that affect protein stability.Conclusions Our study found that there was no significant correlation between each specific mutation and the severity of clinical manifestations.Different patients with the same gene pathogenic variant may have mild or severe clinical manifestations.The correlation between genotype and phenotype needs further study.Three-dimensional protein simulations may provide additional support for the physiopathological mechanism of genetic mutations.