High accuracy of single-molecule real-time sequencing in detecting a rare α-globin fusion gene in carrier screening population.

INTRODUCTION: The α-globin fusion gene between the HBA2 and HBAP1 genes becomes clinically important in thalassemia screening because this fusion gene can cause severe hemoglobin (Hb) H disease when combining with α0 -thalassemia (α0 -thal). Due to its uncommon rearrangement in the α gene cluster without dosage changes, this fusion gene is undetectable by common molecular testing approaches used for α-thal diagnosis. METHODS: In this study, we used the single-molecule real-time (SMRT) sequencing technique to detect this fusion gene in 23 carriers identified by next-generation sequencing (NGS) among 16,504 screened individuals. Five primers for α and ß thalassemia were utilized. RESULTS: According to the NGS results, the 23 carriers include 14 pure heterozygotes, eight compound heterozygotes with common α-thal alleles, and one homozygote. By using SMRT, the fusion mutant was successfully detected in all 23 carriers. Furthermore, SMRT corrected the diagnosis in two "pure" heterozygotes: one was compound heterozygote with anti-3.7 triplication, and the other was homozygote. CONCLUSION: Our results indicate that SMRT is a superior method compared to NGS in detecting the α fusion gene, attributing to its efficient, accurate, and one-step properties.

Application of real-time PCR-based multicolor melting curve with automatic analysis system in pregestational and prenatal thalassemia diagnoses.

BACKGROUND: To evaluate the value of the real-time PCR-based multicolor melting curve analysis (MMCA) with an automatic analysis system used in a mass thalassemia screening and prenatal diagnosis program. METHODS: A total of 18,912 peripheral blood samples from 9456 couples and 1150 prenatal samples were detected by MMCA assay. All prenatal samples were also tested by a conventional method. Samples with unknown melting peaks, unusual peak height ratios between a wild allele and a mutant allele, or a discordant phenotype-genotype match were further studied by using multiplex ligation-dependent probe amplification (MLPA) or Sanger sequencing. All MMCA results were automatically analyzed and manually checked. The consistency between MMCA assay and conventional methods among prenatal samples was investigated. RESULTS: Except for initiation codon (T > G) (HBB:c.2T > G), all genotypes of thalassemia inside the scope of conventional methods were detected by MMCA assay. Additionally, 27 carriers with 10 rare HBB variants, 13 with α fusion gene, 1 with a rare deletion in α globin gene, and 1 with rare HBA variant were detected by using MMCA assay. CONCLUSION: MMCA can be an alternative approach used in routine thalassemia carrier screening and prenatal diagnosis for its high throughput, sufficient stability, low cost, and easy operation.

[Correlation of age, body mass index and obesity-related biochemical indexes with semen quality in males intending for a second child].

OBJECTIVE: To explore the influence of age, body mass index (BMI) and obesity-related biochemical indexes on semen quality in adult males intending to have a second child in Guangzhou. METHODS: We conducted a questionnaire investigation among 632 adult males seeking medical advice on their intention for a second child at Guangzhou Women and Children's Medical Center from August 2017 to July 2018. We obtained their lipid metabolism indicators and semen parameters, and analyzed the correlation of semen quality with age, BMI, obesity-related biochemical indexes, living environment and occupation. RESULTS: Age, BMI, season of sperm extraction, living environment and occupation all influenced the semen quality of the males. Age was correlated negatively with the percentage of progressively motile sperm (PMS) (r = －0.109, P < 0.05), BMI positively with the semen volume (r = 0.103, P < 0.05) but negatively with the percentage of morphologically normal sperm (MNS) (r = －0.138, P < 0.05), high-density lipoprotein (HDL) negatively with PMS (r = －0.168, P < 0.01) and the percentage of immotile sperm (IM) (r = －0.135, P < 0.05), low-density lipoprotein (LDL) negatively with the semen volume (r = －0.124, P < 0.01), PMS (r = －0.127, P < 0.05), sperm concentration (r = －0.121, P < 0.05) and total sperm count (r = －0.210, P < 0.01) but positively with IM (r = 0.140, P < 0.01). Multivariate regression analysis showed BMI and LDL to be independent factors influencing the semen volume, uric acid to be an independent factor influencing semen liquefaction time, age, HDL and LDL to be independent factors influencing PMS, age, and HDL to be independent factors influencing IM, LDL to be independent factors influencing total sperm count, while BMI and TG to be independent factors influencing MNS. CONCLUSIONS: Age, BMI, season of sperm extraction, living environment and occupation may affect the semen quality of the males in Guangzhou.

KFL1 Gene Variants in α-Thalassemia Individuals with Increased Fetal Hemoglobin in a Chinese Population.

Krüppel-like factor 1 (KLF1) is a pleiotropic erythroid transcription factor that is a regulator of definitive erythropoiesis. The aim of this study was to detect KLF1 gene variants in α-thalassemia (α-thal) carriers with an increased Hb F level in a Chinese population, and determine the changes of hematological parameters as a result of interactions between KLF1 gene mutations and α-thal. Subjects with α-thal and Hb F levels of ≥1.0% were selected for further investigation. Direct sequencing was used to detect KLF1 gene mutations. Hematological parameters of subjects with α-thal and concomitant KLF1 gene mutations and those with α-thal alone were compared. The KLF1 gene variants were detected in 46 of 275 (16.7%) individuals with α-thal and Hb F levels of ≥1.0%. The detection rate of KLF1 gene mutations rose correspondingly when the Hb F level increased. For α0-thal carriers, significantly lower mean corpuscular volume (MCV) and mean corpuscular hemoglobin (Hb) (MCH) values were observed in KLF1 gene mutation-positive carriers than that in KLF1 gene mutation-free carriers; conversely, significantly higher Hb A2 and Hb F levels were observed in the former condition rather than in the latter condition. The results of this study indicate that KLF1 gene variants are common in Chinese subjects with α-thal and increased Hb F levels, and KLF1 gene mutations decreased the red blood cell (RBC) indices in α-thal carriers as that in normal adults.

[Population intervention of thalassemia relying on family planning service system].

OBJECTIVE: To set up thalassemia population intervention model in order to decrease the birth of thalassemia major, relying on population and family planning service system. METHODS: Pregnant women and their husbands were educated about thalassemia, and participated in screening and prenatal diagnosis if the couple were carriers of thalassemia in the areas of Huangpu, Panyu, Zengcheng and Tianhe districts of Guangzhou. RESULTS: The network of thalassemia intervention mainly dependent on family planning service system was set up in these regions. A total of 10 695 families participated in thalassemia screening and 16 thalassemia major fetuses were diagnosed in the last two years. No one was thalassemia major in the 8360 newborn. CONCLUSION: Thalassemia population intervention model was set up relying on family planning service system and it significantly decreased the birth of thalassemia major.

[Screening Abnormal Hemoglobin Diseases for Couples of Childbearing Age in Guangzhou City by HPLC].

OBJECTIVE: To investigate the incidence and common types of abnormal hemoglobin diseases of the couples at childbearing age by using high performance liquid chromatography (HPLC) in Guangzhou city. METHODS: The couple of childbearing age in the Birth defect intervention project and Free pre pregnancy health examination were screened from October 2008 to February 2016 in Guangzhou city. The HPLC was used to detect abnormal hemoglobin; The Gap-PCR and reverse dot blot(RDB) were used to detect thalassemia gene deletions. RESULTS: The detection rate of hemoglobinopathies was 1.14% in the couples of childbearing age in Guangzhou city. 8 kinds of abnormal hemoglobin were detected: Hb E in 102 cases(17 cases with α thalassemia) , Hb Q-Thailand in 20 cases(18 cases with α thalassemia, 2 cases with α and ß thalassemia), Hb D-Iran in 4 cases(2 cases with α thalassemia, 1 case with α and ß thalassemia), Hb G-Honolulu in 3 cases(1 case with α thalassemia), Hb J-Bangkok in 2 cases(2 cases with α thalassemia), Hb Osu-Christiansborg in 1 case(with α thalassemia), Hb Hasharon in 1 case(with α thalassemia), Hb Koln in 1 case(with α thalassemia). CONCLUSION: The incidence of abnormal hemoglobin diseases in Guangzhou area has been found to be more high, 8 kinds of abnormal hemoglobin are found by HPLC, the HPLC is an effective way to screen the couples of childbearing age for ß thalassemia and hemoglobinopathies.