Results of carrier screening for Spinal muscular atrophy among 35 145 reproductive-aged individuals from Dongguan region / 中华医学遗传学杂志

OBJECTIVE@#To carry out carrier screening for Spinal muscular atrophy (SMA) in reproductive-aged individuals from Dongguan region and determine the carrier frequency of SMN1 gene mutations.@*METHODS@#Reproductive-aged individuals who underwent SMN1 genetic screening at the Dongguan Maternal and Child Health Care Hospital from March 2020 to August 2022 were selected as the study subjects. Deletions of exon 7 and 8 (E7/E8) of the SMN1 gene were detected by real-time fluorescence quantitative PCR (qPCR), and prenatal diagnosis was provided for carrier couples by multiple ligation-dependent probe amplification (MLPA).@*RESULTS@#Among the 35 145 subjects, 635 were found to be carriers of SMN1 E7 deletion (586 with heterozygous E7/E8 deletion, 2 with heterozygous E7 deletion and homozygous E8 deletion, and 47 with sole heterozygous E7 deletion). The carrier frequency was 1.81% (635/35 145), with 1.59% (29/1 821) in males and 1.82% (606/33 324) in females. There was no significant difference between the two genders (χ² = 0.497, P = 0.481). A 29-year-old woman was found to harbor homozygous deletion of SMN1 E7/E8, and was verified to have a SMN1∶SMN2 ratio of [0∶4], none of her three family members with a [0∶4] genotype had clinical symptoms. Eleven carrier couples had accepted prenatal diagnosis, and one fetus was found to have a [0∶4] genotype, and the pregnancy was terminated.@*CONCLUSION@#This study has determined the SMA carrier frequency in Dongguan region for the first time and provided prenatal diagnosis for carrier couples. The data can provide a reference for genetic counseling and prenatal diagnosis, which has important clinical implications for the prevention and control of birth defects associated with SMA.

Two large novel alpha-globin gene cluster deletions causing alpha(0)-thalassemia in two Chinese families.

INTRODUCTION: Monosomy of terminal 16p13.3 is a relatively common subtelomeric abnormality, most affected individuals presented α-thalassemia, some also have mental retardation, developmental abnormalities and/or speech delay and facial dysmorphism, which is termed ATR-16 syndrome. Here, we reported two novel 16p13.3 deletions involving the α-globin gene cluster and multispecies conserved sequences (MCSs), causing only a phenotype of α-thalassemia. METHODS: Samples were collected from members of the two families and were subjected to haematological and comprehensive genetic analysis. RESULTS: The novel 108 Kb deletion in family A extends from the non-protein coding RNA gene (WASIR2) to the NPRL3 gene, removing MCS-R1 to R3. This deletion should arise de novo because it wasn't detected in both parents. The novel 336 Kb deletion in family B should extend from telomere to âˆ¼ chr16:336000, removing the entire α-globin gene cluster. Carriers of these two deletions presented with microcytosis and hypochromic red cells, in accordance with a phenotype of α0-thalassemia carrier. CONCLUSION: Our study increases the mutation spectrum of α-thalassemia. MCSs deletion should be considered in clinical practice of thalassemia screening and diagnosis.

Hyperhaemolysis in a pregnant woman with a homozygous ß0 -thalassemia mutation and two genetic modifiers.

INTRODUCTION: Patients with a homozygous ß0 -thalassemia mutation usually have a transfusion-dependent ß-thalassemia major phenotype. However, some ß-thalassemia patients present with a relatively mild and even normal phenotype and always have a high level of Hb F induced by genetic modifiers. METHODS: In this study, we identified a homozygous ß0 -thalassemia mutation (HBB: c.126_129delCTTT) in a 36-year-old pregnant woman. She had not presented any clinical symptoms of ß-thalassemia since birth. To investigate her unexpected mild phenotype, known genetic modifiers that ameliorate the severity of ß-thalassemia were analysed. Besides, we described the haematological changes during pregnancy. RESULTS: Two genetic modifiers (a heterozygous KLF1: c.519_525dup mutation; and two homozygous HBS1L-MYB locus SNP variants: rs7776054 and rs9399137) were identified. However, she showed a gradually decreased level of Hb during pregnancy, and serious transfusion complication of hyperhaemolysis was induced and complicated the pregnancy. CONCLUSION: This report is in accordance with previous findings that genetic modifiers can ameliorate the clinical severity of ß-thalassemia, even without obvious clinical symptoms in a prolonged steady state. However, the steady state can be disrupted during pregnancy. In addition, raising awareness of hyperhaemolysis among clinicians treating patients with thalassemia is necessary.

Rapid preimplantation genetic diagnosis of -thalassemia SEA deletion with blastocyst cell whole genome amplification and short fragment Gap-PCR method / 南方医科大学学报

<p><b>OBJECTIVE</b>To develop a rapid preimplantation genetic diagnosis method for -thalassemia SEA deletion based on blastocyst cell whole genome amplification (WGA) combined with short fragment Gap-PCR.</p><p><b>METHODS</b>Using multiple displacement amplification (MDA) WGA technique, we established a double-fluorescent PCR system of the housekeeping genes GAPDH and β-actin for WGA quality testing, and a genotyping PCR system of mutant and normal short sequences for α-thalassemia SEA deletion. The sensitivity and accuracy of this method for diagnosis of -thalassemia SEA deletion were evaluated by detecting lymphocyte samples containing different cell numbers from carriers of SEA deletion. The applicability of this method was evaluated by testing of 12 blastocyst biopsy samples.</p><p><b>RESULTS</b>Detection of lymphocyte samples with different cell numbers using the method developed in this study revealed no ADO in 3-cell samples, and the product quantity of WGA became stable for 4-cell samples. Genotyping of the 10 blastocyst biopsy samples with successful WGA showed a genotype of --/ in 5 samples and / in the other 5 samples, which were consistent with the verification results.</p><p><b>CONCLUSIONS</b>The method developed in this study is a complete testing process for 4-6 blastocyst biopsy cells to allow rapid, accurate, and cost-effective PGD genotyping of -thalassemia SEA deletion using short fragment gap-PCR.</p>

Clinical application of semiconductor gene sequencing in screening thalassemia / 实用医学杂志

Objective To investigate the feasibility of semiconductor gene sequencing technology for thalassemia clinical screening and evaluate its application as compared with the results of PCR technology.Methods 197 visiting patients were randomly selected as prospective samples and200 patients ever diagnosed with thalassemia as previous samples.All the samples were detected by semiconductor technology gene sequencing and PCR technology at the same time and then evaluation of the advantage of semiconductor gene sequencing technology.Results 22 cases of 197 prospective samples were detected as thalassemia mutations by PCR technology,including 18 cases of α-thalassemia,3 cases of β-thalassemia,1 case of oα merge β thalassemia mutations.Semiconductor technology gene sequencing detected another 6 cases of rare type of thalassemia.By semiconductor gene sequencing technology on previous samples,118 cases of α-thalassemia,65 cases of β-thalassemia,17 case of α merge β thalassemia mutations,1 case of thalassemia mutations (HBA 1:c.223G ＞ C) were detected.By statistical analysis,the total coincidence rate of PCR technology and semiconductor gene sequencing was 98.5％,withthe Kappa =0.97(≥ 0.8).Conclusion Semiconductor gene sequencing technology for thalassemia clinical screening is feasible,for it can detect both thalassemia gene type,and new mutation.The results of semiconductor gene sequencing technology are accurate and the technology could be popularized in clinical application.

Analysis of the cause of pregnancy failure with combined MLPA assay for subtelomeric regions and ultrasonography / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the value of multiplex ligation-dependent probe amplification (MLPA) for the detection of chromosome abnormalities in miscarriage tissues, and to correlate the result with ultrasound findings.</p><p><b>METHODS</b>A total of 421 cases of spontaneous abortions and fetal deaths were detected with the MLPA method.</p><p><b>RESULTS</b>Among the 421 samples, 232 (55.11%) had an abnormal MLPA result. For the 286 cases derived from < 13 weeks pregnancy, 206 (72.03%) were abnormal. For the 49 cases from 14-19 weeks pregnancy, 14 (28.57%) were abnormal. For the 86 cases derived after 20 weeks pregnancy, 12 (13.95%) were abnormal. Among the 117 cases with abnormal ultrasound findings, 33 cases (28.21%) had an abnormal MLPA result, 28 out of the 33 cases were numerical chromosome abnormality, 4 cases were chromosome microdeletion and/or micro duplication, 1 case had both numerical abnormality and microduplication. For those with abnormal ultrasound findings for the neck region, fetal edematous syndrome, multiple malformations and digestive system, the detection rates for MLPA were 71.4%, 58.8%, 37.8%, and 9.1%, respectively. For those with abnormal finding of cardiac system, nervous system, face, skeletal system and urinary system, none was found with positive results of MLPA.</p><p><b>CONCLUSION</b>Numerical chromosomal abnormalities account for the majority of cases with spontaneous abortion. With the increase of gestational age, the occurrence of chromosomal abnormalities gradually declines. Combined ultrasound and MLPA assay can improve the detection rate and accuracy for chromosomal abormalities.</p>

Application of MLPA for analysis of chromosomal unbalances / 国际检验医学杂志

Objective To valuate the applicability of multiplex ligation‐dependent probe amplication (MLPA ) for detection of chromosomal unbalance .Methods Aneuploid and subtelomeric MLPA technology were used to analyze 6 samples with chromosom‐al unbalances ,confirmed by karyotype analysis .Results All samples were identified to have abnormal signal of corresponding probes .The extent of unbalances contained subtelomeric region .Conclusion MLPA technology could have important role in diag‐nosis of chromosomal unbalance ,which could complement conventional karyotype analysis .