A Krüppel-Like Factor 1 Gene Mutation Ameliorates the Severity of ß-Thalassemia: A Case Report.

Patients with the ß0/ß0 type of ß-thalassemia (ß-thal) usually present as ß-thal major (ß-TM), and are transfusion-dependent. However, the clinical and hematological features of ß-thal can be modulated by different modifiers, resulting in a wide range of clinical severity even in patients with the same genotypes. We report a Chinese family with twin brothers, both of whom had the same genotype of ß0/ß0. One twin was diagnosed as ß-TM at 4 months of age and had regularly been transfused; conversely the other twin with a KLF1 (Krüppel-like factor 1) gene mutation, behaved as ß-thal intermedia (ß-TI), and had never been transfused. Our findings indicate that KLF1 mutations have a role in modulating the phenotypic severity of ß-thal. The exact investigation of KLF1 modifiers is necessary in areas where globin gene disorders are most prevalent. This will be helpful in genetic counseling and optimizing the guidelines for prenatal diagnosis (PND) programs.

Pre Gestational Thalassemia Screening in Mainland China: The First Two Years of a Preventive Program.

In this study, we report the experience of a pre gestational thalassemia screening program at a single center in Southern China. Free thalassemia screening, genetic counseling and prenatal diagnosis (PND) for couples planning pregnancy were implemented over a 2-year period. Among a total of 83,062 screened individuals (41,531 couples), the allele frequencies of ß-thalassemia (ß-thal), - -SEA and - -THAI deletions were 3.79, 5.75 and 0.028%, respectively. Out of the 41,531 couples, 11,039 couples had at least one partner who had a positive screening test; of these, 455 at-risk couples (1.07%) were identified, including 68 (0.16%) for ß-thal, 162 (0.39%) for Hb Bart's (γ4) hydrops fetalis, 190 (0.46%) for deletional Hb H (ß4) disease and 25 (0.06%) for nondeletional Hb H disease. Of the 455 at-risk couples, 90 were already pregnant and 66 underwent PND at 10-13 weeks' gestation, resulting in 15 affected fetuses. The remaining 355 at-risk couples were still preparing for pregnancy, and they were on the list for follow-up. There is considerable scope for facilitating timely PND through improved organization and screening strategy. The pre pregnancy screening is a feasible and effective approach to thalassemia prevention.

A Novel Frameshift Mutation at Codons 138/139 (HBB: c.417_418insT) on the ß-Globin Gene Leads to ß-Thalassemia.

We describe a new ß-thalassemic mutation in a Chinese subject. This allele develops by insertion of one nucleotide (+T) between codons 138 and 139 in the third exon of the ß-globin gene. The mutation causes a frameshift that leads to a termination codon at codon 139. In the heterozygote, this allele has the phenotype of classical ß-thalassemia (ß-thal) minor.

Hb Hornchurch [ß43(CD2)Glu→Lys; HBB: c.130G>A] Compromises the Molecular Diagnosis of ß-Thalassemia in a Chinese Family.

The combination of ß-thalassemia (ß-thal) and a hemoglobin (Hb) variant is not uncommon in regions with a high prevalence of thalassemia. Although most of the ß-globin chain variants will not aggravate the ß-thal, some can compromise the accurate molecular diagnosis. In this study, we present a rare case of coinheritance of ß-thal and Hb Hornchurch [ß43(CD2)Glu→Lys; HBB: c.130G>A], that compromises the molecular diagnosis of homozygous ß-thal.

Hydrops Fetalis Associated with Compound Heterozygosity for Hb Zurich-Albisrieden (HBA2: C.178G > C) and the Southeast Asian (- -SEA/) Deletion.

Hb Zurich-Albisrieden [HBA2: c.178G > C; α59(E8)Gly→Arg (α2)] is a rare nondeletional α-thalassemia (α-thal) that results from a nucleotide substitution at codon 59 of the α2-globin gene. In this report, we present a fetus with cardiomegaly, enlarged placenta and increased middle cerebral artery-peak systolic velocity (MCA-PSV) at 25 weeks' gestation. Fetal blood sampling revealed the severe anemia [hemoglobin (Hb) level being 5.5 g/dL] and Hb H (ß4) disease-like hematological findings with Hb Bart's (γ4) level of 30.7%. Molecular analysis of the family found that the father was an Hb Zurich-Albisrieden carrier, the mother heterozygous for the - -SEA α0-thal deletion, and the fetus was a compound heterozygote for Hb Zurich-Albisrieden and the - -SEA α0-thal deletion. Therefore, this was a rare case of Hb Bart's hydrops fetalis associated with Hb Zurich Albisrieden.

Diagnostic Dilemma of Hb Perth [ß32(B14)Leu→Pro; HBB: c.98T > C] in Mainland China.

Unstable hemoglobin (Hb) variants represent a rare etiology of congenital hemolytic anemia. Correct diagnosis can be a challenge due to the relative rarity or lack of awareness of this disorder. We report an 18-month-old girl, who presented with a long-standing hemolytic anemia. Her diagnosis of unstable Hb Perth [ß32(B14)Leu→Pro, HBB: c.98T > C] had not been made until gene sequencing of the ß-globin gene was performed.

A New δ-Globin Gene Variant: Hb A2-Fengshun [δ121(GH4)Glu→Lys (HBD: c.364G > A)].

An elevated Hb A2 (α2δ2 level) is a diagnostic marker for heterozygous ß-thalassemia (ß-thal). Mutations in the δ-globin gene can cause decreased expression of Hb A2, compromising screening for heterozygous ß-thal. In this report, we describe a novel missense mutation of the δ-globin [Hb A2-Fengshun or δ121(GH4)Glu→Lys, HBD: c.364G > A] in a Chinese individual who had coinherited a heterozygous ß-thal with a normal Hb A2 level.

Consequences of Delayed Prenatal Diagnosis of ß-Thalassemia in Mainland China.

ß-Thalassemia (ß-thal) is one of the most common inherited single gene disorders in the world. The aim of this study was to describe the gestational age at prenatal diagnosis (PND) for ß-thal in at-risk women in mainland China. All pregnant women at-risk for ß-thal and undergoing PND at a Mainland Chinese tertiary obstetric center between January 2005 and December 2014 were included. Information required for the survey was obtained from prenatal records and delivery charts. In total, 1307 women underwent PND for ß-thal. The mean gestational age for the procedure was 18.5 weeks. There were 384 (29.0%) women with fetal diagnosis in early trimester (<14 weeks), 715 (55.0%) in early second trimester (14-24 weeks), and 208 (16.0%) in late second trimester or beyond (>24 weeks). Although the proportion of patients undergoing early PND increased along with the time span, the mean n gestational age was not decreased significantly during the study period. The delay in PND deprived couples of the opportunity to make informed decisions early in pregnancy.

Evidence of Selection for the α-Globin Gene Deletions and Triplications in a Southern Chinese Population.

α(+)-Thalassemia (α(+)-thal) is common in Southern China. The high frequency could be due to over dominant selection through malaria. Two molecular mechanisms that produce α(+)-thal have been defined; one results in the -α(3.7) (rightward) deletion and reciprocal ααα(anti 3.7) triplication, and the other one results in the -α(4.2) (leftward) deletion and reciprocal ααα(anti 4.2) triplication. Considering that each de novo event produced a chromosome with an α gene deletion and a chromosome with an α triplication, if there is no favorable allele, one would expected to find the same allelic frequencies. We found a favorable selection for the -α(3.7) deletion in the Chinese population, and we also found that the α triplication is not as rare as was first thought, especially for the ααα(anti 3.7) triplication.

Implementation of newborn screening for hemoglobin h disease in mainland china.

Hemoglobin H disease is the most severe non-fatal form of α-thalassemia syndrome characterized by pronounced microcytic hypochromic hemolytic anemia. It is predominantly seen in Southeast Asia, the Middle East and the Mediterranean. Studies suggest that hemoglobin H disease is not as benign a disorder as previously thought. Newborn screening for hemoglobin H disease is especially appealing because the screening test is based on the detection of hemoglobin Bart's (γ4) that is only possible within the newborn period. In this study, we reported on a 4-year period of newborn screening program at a mainland Chinese hospital, which detected 35 babies with hemoglobin H disease in a total of 26 152 newborns. The overall prevalence for hemoglobin H disease among all newborns in southern China is ~1 in 1,000. These children need appropriate follow-up and potential comprehensive care during their growth and development.

Co-inheritance of α-thalassaemia and ß-thalassaemia in a prenatal screening population in mainland China.

OBJECTIVE: To determine the prevalence of α-thalassaemia in ß-thalassaemia individuals in a Chinese population. METHODS: The standard diagnostic marker for ß-thalassaemia was elevation of the Hb A2 level (>3.5%) with low mean corpuscular volume. The common α-thalassaemia mutations were studied by molecular analysis in all identified ß-thalassaemia carriers. RESULTS: A prevalence rate of 3.3% for ß-thalassaemia was found in our population; α- and ß-thalassaemia interactions were found to co-exist in 17.8% of the ß-thalassaemia carriers. The -SEA deletion was the most common α-thalassaemia mutation co-inherited with ß-thalassaemia, followed by the -α3.7 deletion, the -α4.2 deletion, Hb Quong Sze, and Hb Constant Spring. CONCLUSION: Our results suggest that it could be valuable to study co-existing α-globin mutations in subjects with ß-thalassaemia trait in a prenatal screening programme, especially in populations with a high prevalence of haemoglobinopathies.

A new hemoglobin variant: Hb Henan [ß90(F6)Glu → Gln; HBB: c.271G < C].

We have identified a new ß chain hemoglobin (Hb) variant in a Chinese individual. Sequencing of the ß-globin gene revealed a mutation in exon 2 at nucleotide 271, which results in the replacement of a glutamic acid by glutamine at codon 90 [ß90(F6)Glu → Gln; GAG > CAG; HBB: c.271G > C] that we have named Hb Henan.

Case report: prenatal diagnosis of Hb Hammersmith [ß42(CD1)Phe→Ser; HBB: c.128T > C] in a family with an adult male patient.

Hb Hammersmith [ß42(CD1)Phe → Ser; HBB: c.128T > C] is a rare, unstable hemoglobin (Hb) variant. In this case report, we describe another male case of Hb Hammersmith. A 39-year-old male had hemolytic anemia, cyanosis and splenomegaly since 6 months after birth. He passed the disease allele to his daughter, a 3-year-old girl, who also had hemolytic anemia and splenomegaly. This mutation was not identified in the parents and two brothers of the father. Early prenatal diagnosis was performed in the second pregnancy in this family. This is the first case of Hb Hammersmith in an adult male patient.

Newborn screening for Hb H disease by determination of Hb Bart's using the Sebia capillary electrophoresis system in southern China.

Hb H (ß4) disease is an inherited hemoglobin (Hb) defect in which three of the four α-globin genes are deleted or dysfunctional. The clinical manifestations vary widely from mild asymptomatic anemia to a severely anemic state. Recent literature suggests that Hb H disease is not as benign a disorder as previously thought. Newborn screening for Hb H disease is especially appealing because the screening test is based on the detection of Hb Bart's (γ4) that is only possible within the newborn period. In a 2-year period of newborn screening, 18 babies were found to have Hb H disease in a total of 9490 newborns. The overall prevalence for Hb H disease among all newborns in southern China is approximately 1 in 500. The correct diagnosis would allow affected infants to be properly cared for and reduce mortality rate.

KLF1 gene mutations in Chinese adults with increased fetal hemoglobin.

We investigated the Krüppel-like factor 1 (KLF1) gene mutations in Chinese adults with increased Hb F levels (>1.5%) referred to our laboratory for thalassemia screening. Functionally effective KLF1 mutations were identified in five out of 140 samples with an elevated Hb F (1.9-11.4%). Only two different KLF1 mutations were detected. Functional KLF1 mutations were not identified in the matched cohort of 110 samples with normal Hb F values (<1.0%). The KLF1 mutations could be one of the causes of hereditary persistence of fetal hemoglobin (HPFH) in regions where thalassemias are common.

Prenatal control of nondeletional α-thalassemia: first experience in mainland China.

OBJECTIVE: To demonstrate the performance of nondeletional α-thalassemia prevention at a mainland Chinese hospital. METHODS: A prenatal control program for nondeletional hemoglobin H (Hb H) disease was conducted from January 2010 to June 2012. All couples were screened for α-thalassemia trait, and for couples in whom one partner was tested positive for α(0) -thalassemia, the other was subjected to screening for Hb Constant Spring and Hb Quong Sze mutations. Prenatal diagnoses were offered in pregnancies of couples at-risk for nondeletional Hb H disease. RESULTS: Of the 30,152 couples screened, 18 (0.06%) were diagnosed as at risk for nondeletional Hb H disease. There were other 13 at-risk couples who were referred to prenatal diagnosis because they had previously an affected child. Of the 31 cases with prenatal invasive tests, 11 (35.5%) had diagnosis by chorionic villous sampling, and 20 (64.5%) had amniocentesis. Totally, 12 fetuses were diagnosed with nondeletional Hb H disease, and all of the affected pregnancies were terminated. CONCLUSION: Implementation of a prevention and control program accompanying with a referral system for prenatal diagnosis is technically feasible in southern China, and a number of nondeletional Hb H disease have been prevented during the past 3 years of operation.

Analysis of δ-globin gene mutations in the Chinese population.

Although δ-globin gene (HBD MIM#142000) mutations have no immediate physical consequence, it can interfere with the diagnosis of ß-thalassemia (ß-thal), which can be severe. In the present study, of 40,863 samples referred for thalassemia trait screening, 167 samples with lower than expected Hb A(2) levels, in the presence or absence of a second Hb A(2) fraction, were selected for our analysis and 152 samples (0.4%) were positive for δ-globin gene mutations. Twenty-one different mutations were detected, and of these 12 have not been previously described. We found that -77 (T>C) was the most common mutation in Chinese followed by -30 (T>C), together accounting for almost 82.3% of the total number of δ-globin gene defects. Since compound heterozygotes for ß-thal and a δ-globin gene mutation may have low mean cell volume (MCV) and normal Hb A(2) levels, and therefore be overlooked as ß-thal heterozygotes, a detailed molecular analysis for both α- and ß-thal is necessary, especially when one partner has been identified to have ß-thal trait.