Most adults with severe HbSC disease are not treated with hydroxyurea.

Sickle cell hemoglobin SC (HbSC) disease is the second most frequent sickle cell disease (SCD) genotype after sickle cell anemia (HbSS). Globally, ∼55 000 newborns with HbSC are delivered annually, with the highest HbC gene frequency in West Africa. In Ghana, 40% of adults visiting the Ghana Institute of Clinical Genetics SCD clinic have HbSC. Unlike HbSS, hydroxyurea use is not routinely recommended for individuals with HbSC because of the perceived high-risk to benefit ratio. To test the hypothesis that at least 5% of adults with HbSC will meet the American Society of Hematology criteria for severe disease, we conducted a retrospective descriptive cohort study of all individuals with HbSC (≥18 years) who visited the clinic in 2019. Adults with HbSC aged from 18 to 45 years were selected. We identified a comparison group of 639 individuals with HbSS and matched the frequency based on the age and sex of individuals with HbSC. Severe disease was defined as a history of ≥3 SCD-associated moderate or severe pain episodes per year, history of acute chest syndrome, and severe symptomatic chronic anemia that interferes with daily activities or quality of life. The study end points were the proportion of individuals with SCD who met the definition of severe disease and were eligible for hydroxyurea. In total, 64 of 639 (10.0%) individuals with HbSC met the eligibility criteria for hydroxyurea therapy compared with 154 of 639 (24.1%) individuals with HbSS. Less than 1% and 3% of individuals with severe HbSC and HbSS, respectively, were routinely prescribed with hydroxyurea in this tertiary care medical center.

Epigenetic analysis in placentas from sickle cell disease patients reveals a hypermethylation profile.

Pregnancy in Sickle Cell Disease (SCD) women is associated to increased risk of clinical and obstetrical complications. Placentas from SCD pregnancies can present increased abnormal findings, which may lead to placental insufficiency, favoring adverse perinatal outcome. These placental abnormalities are well known and reported, however little is known about the molecular mechanisms, such as epigenetics. Thus, our aim was to evaluate the DNA methylation profile in placentas from women with SCD (HbSS and HbSC genotypes), compared to uncomplicated controls (HbAA). We included in this study 11 pregnant women with HbSS, 11 with HbSC and 21 with HbAA genotypes. Illumina Methylation EPIC BeadChip was used to assess the whole placental DNA methylation. Pyrosequencing was used for array data validation and qRT-PCR was applied for gene expression analysis. Our results showed high frequency of hypermethylated CpGs sites in HbSS and HbSC groups with 73.5% and 76.2% respectively, when compared with the control group. Differentially methylated regions (DMRs) also showed an increased hypermethylation status for the HbSS (89%) and HbSC (86%) groups, when compared with the control group methylation data. DMRs were selected for methylation validation (4 DMRs-HbSS and 3 DMRs the HbSC groups) and after analyses three were validated in the HbSS group, and none in the HbSC group. The gene expression analysis showed differential expression for the PTGFR (-2.97-fold) and GPR56 (3.0-fold) genes in the HbSS group, and for the SPOCK1 (-2.40-fold) and ADCY4 (1.80-fold) genes in the HbSC group. Taken together, these data strongly suggest that SCD (HbSS and HbSC genotypes) can alter placental DNA methylation and lead to gene expression changes. These changes possibly contribute to abnormal placental development and could impact in the clinical course, especially for the fetus, possibly leading to increased risk of abortion, fetal growth restriction (FGR), stillbirth, small for gestational age newborns and prematurity.

Another 'BEE'? - Brain-Eye-Ear (BEE) Disease Secondary to HbSC Disease Masquerading as Multiple Sclerosis.

Recurrent episodes of neurological dysfunction and white matter lesions in a young adult raise suspicion for multiple sclerosis (MS). However, occlusive retinopathy, hearing loss and absence of CSF oligoclonal bands are atypical for MS and should make the clinician consider an alternative diagnosis. We describe a man with hearing loss, visual signs and symptoms, and an accumulating burden of brain lesions, who was treated for a clinical diagnosis of MS for nearly two decades. Genetic testing revealed a unifying diagnosis.

Sickle cell disease: A distinction of two most frequent genotypes (HbSS and HbSC).

Sickle cell disease (SCD) consists of a group of hemoglobinopathies in which individuals present highly variable clinical manifestations. Sickle cell anemia (SCA) is the most severe form, while SC hemoglobinopathy (HbSC) is thought to be milder. Thus, we investigated the clinical manifestations and laboratory parameters by comparing each SCD genotype. We designed a cross-sectional study including 126 SCA individuals and 55 HbSC individuals in steady-state. Hematological, biochemical and inflammatory characterization was performed as well as investigation of previous history of clinical events. SCA patients exhibited most prominent anemia, hemolysis, leukocytosis and inflammation, whereas HbSC patients had increased lipid determinations. The main cause of hospitalization was pain crises on both genotypes. Vaso-occlusive events and pain crises were associated with hematological, inflammatory and anemia biomarkers on both groups. Cluster analysis reveals hematological, inflammatory, hemolytic, endothelial dysfunction and anemia biomarkers in HbSC disease as well as SCA. The results found herein corroborate with previous studies suggesting that SCA and HbSC, although may be similar from the genetic point of view, exhibit different clinical manifestations and laboratory alterations which are useful to monitor the clinical course of each genotype.

Polymorphisms in genes that affect the variation of lipid levels in a Brazilian pediatric population with sickle cell disease: rs662799 APOA5 and rs964184 ZPR1.

This cross-sectional study investigated associations between SNPs in metabolizing lipid genes, alpha-thalassemia and laboratory parameters in two forms of sickle cell disease (SCD), sickle cell anemia (SCA) and hemoglobin SC disease (HbSC) in a pediatric population. Among the groups SCA and HbSC was found a higher proportion of increased triglycerides (TG) in SCA. High levels of TG were significantly associated with lower hemoglobin (p = 0.006) and HDL-C (p = 0.037), higher white blood cell count (p = 0.027), LDH (p = 0.004) and bilirubins (p < 0.05) in SCD. Patients with HDL-C ≤40 mg/dL had higher markers hemolytic levels. Therapy of HU significantly influenced several hematological and biochemical parameters but not lipid fractions. Genotypes of the APOA5 rs662799 were not associated with lipid levels. The G-risk allele rs964184/ZPRI ZNF259/ZPR1 gene (GC + GG genotypes) was associated with increased levels of TG in children ≥10 years old (p = 0.045) and the atherogenic ratio TG/HDL-C (p = 0.032) in SCD. The use of HU improves levels of hemolysis and inflammation markers in SCD with high TG and, while not interfering with lipid levels, seems to overlap the effect of the G-risk allele in on them. This study reported for the first time that rs964184 SNP could be a genetic modifier of TG in SCD.

Sequential development of human herpes virus 8-positive diffuse large B-cell lymphoma and chronic myelomonocytic leukemia in a 59 year old female patient with hemoglobin SC disease.

Hematolymphoid neoplasms, including lymphoma and myeloid neoplasms, can occur in patients with sickle cell disease (SCD) or equivalent hemoglobinopathy, but an underlying connection between the two conditions has yet to be fully determined. Herein, we report a unique case of sequential development of two separate hematolymphoid neoplasms, human herpes virus 8 (HHV8)-positive diffuse large B-cell lymphoma (DLBCL) and chronic myelomonocytic leukemia, in a 59 year-old African American female with hemoglobin SC disease. While etiology of immunodeficiency is unknown, the potential causes include hydroxyurea therapy, disease related immunomodulation, chronic inflammation, and relatively old age. The leukemia cells demonstrated profound trilineage dysplasia and harbored complex cytogenetic abnormalities with loss of chromosome 5q and 7q, which are often observed in therapy-related myeloid neoplasms. Besides the potential causes listed above, we propose that myeloid leukemia in this setting may result from genomic changes due to excessive hematopoietic replication triggered by a hemolysis-induced cytokine storm. While myeloid neoplasms in the setting of SCD seems to herald a dismal clinical outcome per the literature, the HHV8-positive DLBCL in our case was apparently indolent, opposing the current perception of its clinical outcome.

Cardiac manifestations in sickle cell disease varies with patient genotype.

Cardiac involvement is well characterized in sickle cell anaemia (SCA) but cardiac features associated with Haemoglobin SC (HbSC) disease are mostly unknown. We compared 60 patients with HbSC disease (median age 31 years, 25 men) to 60 SCA patients and 60 controls matched for age and gender. Left ventricular ejection fraction (LVEF), left ventricle (LV) mass index (LVMi), cardiac index and peak tricuspid regurgitation velocity (TRV) were measured using echocardiography. LV filling pressures were assessed using the ratio of early diastolic transmitral velocity to tissue velocity (E/e' ratio). The LVMi was higher in both genotypes compared to controls. However, whereas LV hypertrophy was observed only in 3(5%) HbSC patients, this condition was diagnosed in 27(45%) SCA patients (P < 0·0001). While cardiac index and TRV were similar in HbSC compared to controls, SCA patients exhibited elevated cardiac output and TRV. LVEF was similar in the 3 groups. However, both genotypes had a higher E/e' ratio compared to controls. Cardiac involvement in SCA was related to anaemia and haemolysis, while LV diastolic dysfunction and TRV in HbSC disease patients were related to arterial hypertension and overweight comorbidities. In summary, cardiac involvement and its determinants are different in HbSC disease and SCA. Patient's genotype should be considered with regard to the echocardiographic indications and findings.

Abnormal expression of inflammatory genes in placentas of women with sickle cell anemia and sickle hemoglobin C disease.

Sickle cell disease (SCD) is a complex disease that is characterized by the polymerization of deoxyhemoglobin S, altered red blood cell membrane biology, endothelial activation, hemolysis, a procoagulant state, acute and chronic inflammation, and vaso-occlusion. Among the physiological changes that occur during pregnancy, oxygen is consumed by fetal growth, and pregnant women with SCD are more frequently exposed to low oxygen levels. This might lead to red blood cells sickling, and, consequently, to vaso-occlusion. The mechanisms by which SCD affects placental physiology are largely unknown, and chronic inflammation might be involved in this process. This study aimed to evaluate the gene expression profile of inflammatory response mediators in the placentas of pregnant women with sickle cell cell anemia (HbSS) and hemoglobinopathy SC (HbSC). Our results show differences in a number of these genes. For the HbSS group, when compared to the control group, the following genes showed differential expression: IL1RAP (2.76-fold), BCL6 (4.49-fold), CXCL10 (-2.12-fold), CXCR1 (-3.66-fold), and C3 (-2.0-fold). On the other hand, the HbSC group presented differential expressions of the following genes, when compared to the control group: IL1RAP (4.33-fold), CXCL1 (3.05-fold), BCL6 (4.13-fold), CXCL10 (-3.32-fold), C3 (-2.0-fold), and TLR3 (2.38-fold). Taken together, these data strongly suggest a differential expression of several inflammatory genes in both SCD (HbSS and HbSC), indicating that the placenta might become an environment with hypoxia, and increased inflammation, which could lead to improper placental development.

Original Research: Acute chest syndrome in sickle cell disease: Effect of genotype and asthma.

Sickle cell disease is a severe hemoglobinopathy caused by mutations in the beta globin genes. The disorder has protean manifestations and leads to severe morbidity and early mortality. Acute chest syndrome (ACS) is a common complication and in the USA is the leading cause of death in patients with sickle cell disease. Care of patients with sickle cell disease is complex and typically involves both primary care physicians and hematology subspecialists. The purpose of this study was first to attempt to validate in a pediatric sickle cell patient cohort associations between ACS and sickle cell disease genotype and between ACS and asthma as a comorbidity. The second purpose of the study was to study in a typical community the frequency with which asthma associated with ACS was addressed in terms of electronic medical record integration, pulmonary subspecialty consultation for management of asthma, and completion of pulmonary function testing (PFTs). A retrospective study of the electronic medical record of a children's hospital that provides most of the medical care for children in a portion of western New York state was performed. We found that ACS was more common in the sickle cell disease genotypes SS and S/beta-thalassemia-null, and that ACS was more frequent in patients treated for asthma. We also found that despite the use of a comprehensive electronic medical record, there was poor documentation of ACS and asthma episodes in the problem lists of patients with sickle cell disease, and that most patients with sickle cell disease with ACS or asthma failed to receive formal consultation services from pediatric pulmonary subspecialists.

Hereditary Persistence of Fetal Hemoglobin Caused by Single Nucleotide Promoter Mutations in Sickle Cell Trait and Hb SC Disease.

Hereditary persistence of fetal hemoglobin (HPFH) can be caused by point mutations in the γ-globin gene promoters. We report three rare cases: a child compound heterozygous for Hb S (HBB: c.20A > T) and HPFH with a novel point mutation in the (A)γ-globin gene promoter who had 42.0% Hb S, 17.0% Hb A and 38.0% Hb F; a man with Hb SC (HBB: c.19G > A) disease and a point mutation in the (G)γ-globin gene promoter who had 54.0% Hb S, 18.0% Hb C and 25.0% Hb F; a child heterozygous for Hb S and HPFH due to mutations in both the (A)γ- and (G)γ-globin gene promoters in cis [(G)γ(A)γ(ß(+)) HPFH], with 67.0% Hb A, 6.5% Hb S and 25.0% Hb F.

Chronic kidney disease is common in sickle cell disease: a cross-sectional study in the Tema Metropolis, Ghana.

BACKGROUND: Renal involvement in sickle cell disease (SCD) contributes significantly to morbidity and mortality. The aim of this study was to determine the prevalence of chronic kidney disease (CKD) amongst SCD patients, and how basic clinical variables differ across haemoglobin genotypes. METHODS: A hospital-based cross-sectional study conducted from December 2013 to May 2014 at the Sickle cell clinic of the Tema General Hospital. One hundred and ninety-four (194) participants with SCD, receiving medical care at the outpatient sickle cell clinic were enrolled onto the study. A structured questionnaire was administered to obtain information on demography, clinical history, blood pressure and anthropometry. Blood and urine samples were taken for serum creatinine and proteinuria determination respectively. The estimated GFR (eGFR) was calculated using the CKD-EPI and Schwartz equations. CKD was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) guidelines. Analysis was performed using GraphPad prism and P <0.05 was considered statistically significant. RESULTS: CKD was present in 39.2% of participants. Using KDIGO guidelines, 40.8% of the HbSS participants had stage 1 CKD and none had stage 2 CKD. In addition, 30.8% of the HbSC participants had stage 1 CKD and 3.8% had stage 2 CKD. There was a trend of increasing age across CKD stages and stage 2 CKD participants were oldest (P < 0.001). CONCLUSION: Results from the current study suggest that CKD is common amongst SCD patients and prevalence and intensity increases with age. Proteinuria and CKD was more common in HbSS genotype than in HbSC genotype.

Elevated hypercoagulability markers in hemoglobin SC disease.

Hemoglobin SC disease is a very prevalent hemoglobinopathy; however, very little is known about this condition specifically. There appears to be an increased risk of thromboembolic events in hemoglobin SC disease, but studies evaluating the hemostatic alterations are lacking. We describe the findings of a cross-sectional observational study evaluating coagulation activation markers in adult patients with hemoglobin SC, comparing them with those in sickle cell anemia patients and healthy controls. A total of 56 hemoglobin SC and 39 sickle cell anemia patients were included in the study, all in steady state, and 27 healthy controls. None of the patients was taking hydroxyurea. Hemoglobin SC patients had a significantly up-regulated relative expression of tissue factor, as well as elevations in thrombin-antithrombin complex and D-dimer, in comparison to controls (P<0.01). Hemoglobin SC patients had lower tissue factor expression, and thrombin-antithrombin complex and D-dimer levels when compared to sickle cell anemia patients (P<0.05). Markers of endothelial activation (soluble thrombomodulin and soluble vascular cell adhesion molecule-1) and inflammation (tumor necrosis factor-alpha) were both significantly elevated in hemoglobin SC patients when compared to controls, being as high as the levels seen in patients with sickle cell anemia. Overall, in hemoglobin SC patients, higher hemolytic activity and inflammation were associated with a more intense activation of coagulation, and hemostatic activation was associated with two very prevalent chronic complications seen in hemoglobin SC disease: retinopathy and osteonecrosis. In summary, our results demonstrate that hemoglobin SC patients have a hypercoagulable state, although this manifestation was not as intense as that seen in sickle cell anemia.

Blood typing profile of a school-aged population of a North Togo township.

The aim of this study was the determination of hemoglobin (Hb) variants and ABO blood groups in a school population aged 6 to 9 years in the township of Agbandé-Yaka in North Togo. A cross-sectional study was carried out on 570 children of four primary schools at Agbande-Yaka, between March and July 2010. Hemoglobin characterization was done by alkaline buffer electrophoresis and the blood types ABO-Rhesus (Rh) D by immuno-hematological methods. A Hb variant was detected in 37.0% of the schoolchildren. Among them, the AS trait accounted for 11.9% and the AC trait for 20.2%. Homozygous Hb S (HBB: c.20A>T) was not found but Hb C (HBB: c.19G>A) appeared at a frequency of 3.3%, while compound heterozygotes carrying Hb SC were seen at a frequency of 1.6%. The O, B and A blood groups accounted for 49.0, 26.8 and 21.9%, respectively. The Hb anomalies reached a high prevalence in this school population. These results are remarkable by the absence of homozygous Hb S individuals compared to homozygous Hb C individuals, which were as numerous as expected. The frequencies of the ABO blood groups are similar to what has been found in other West African populations.

Hb Fulton-Georgia [α20(B1)His→Pro; HBA1: c.62A>C]: a new α-globin variant coinherited with α-thalassemia-2 (3.7 kb deletion) and Hb SC disease.

We report a novel hemoglobin (Hb) variant that we named Hb Fulton-Georgia, caused by a point mutation in exon 1/codon 20 of the α-globin gene [α20(B1)His→Pro; HBA1: c.62A>C]. This α chain variant was identified in an adult African-American female with Hb SC disease who was also heterozygous for the α-thalassemia-2 (α-thal-2) (3.7 kb deletion or αα/-α(3.7)). The Hb Fulton-Georgia mutation was located on the intact α1-globin gene not involved by α-thal-2. Molecular models indicated that the α20 residue of Hb Fulton-Georgia was the first amino acid of the B helix, and was not involved in α1/ß1 or α1/ß2 contacts in Hb S [ß6(A3)Glu→Val; HBB: c.20A>T] or Hb C [ß6(A3)Glu→Lys; HBB: c.19G>A] tetramers. Furthermore, the histidine→proline substitution at α20 did not disrupt the helical structure. High performance liquid chromatography (HPLC) detected Hb Fulton-Georgia in 16.0% of total Hb, consistent with inheritance on the α1 gene. Coinheritance of Hb Fulton-Georgia, heterozygous α-thal-2 and Hb SC disease was associated with a mild phenotype, consisting of microcytosis and anisocytosis, but no anemia or other hematological abnormality.

Factors that influence parents' experiences with results disclosure after newborn screening identifies genetic carrier status for cystic fibrosis or sickle cell hemoglobinopathy.

OBJECTIVE: Newborn screening (NBS) identifies genetic carriers for sickle cell hemoglobinopathy and cystic fibrosis. We aimed to identify factors during initial NBS carrier results disclosure by primary care providers (PCPs) that influenced parents' experiences and reactions. METHODS: Open-ended responses from telephone interviews with 270 parents of carriers were analyzed using mixed-methods. Conventional content analysis identified influential factors; chi-square tests analyzed relationships between factors and parent-reported reactions. RESULTS: Parents reported positive (35%) or negative (31%) reactions to results disclosure. Parents' experiences were influenced by specific factors: content messages (72%), PCP traits (47%), and aspects of the setting (30%). Including at least one of five specific content messages was associated (p<0.05) with positive parental reactions; omitting at least one of four specific content messages was associated (p<0.05) with negative parental reactions. Parents reported positive reactions when PCPs avoided jargon or were perceived as calm. Parents reported negative reactions to jargon usage and results disclosure by voicemail. CONCLUSION: Parents identified aspects of PCP communication which influenced their reactions and results disclosure experiences. PRACTICE IMPLICATIONS: Our findings suggest ways PCPs may improve communication of carrier results. PCPs should provide specific content messages and consider how their actions, characteristics, and setting can influence parental reactions.

Polysomnographic characteristics of a referred sample of children with sickle cell disease.

STUDY OBJECTIVES: To describe polysomnographic parameters and their clinical correlates in a referred sample of children with sickle cell disease (SCD). METHODS: This was a retrospective medical record review of 55 consecutive children aged 2-18 years with SCD (hemoglobin [Hb] SS and Hb SC genotypes) undergoing polysomnography for evaluation of sleep disordered breathing. Polysomnography values were compared between SCD genotypes, 4 age groups, and adenotonsillectomy status using descriptive and nonparametric statistics. RESULTS: Obstructive sleep apnea (OSA) was diagnosed in 38/55 (69%) children. Polysomnographic parameters differed significantly between Hb SS and Hb SC genotypes only on arterial oxyhemoglobin saturation (SpO2; 95.2 +/- 3.8 vs. 98.0 +/- 0.8, respectively, p < 0.01) and percent of sleep time below SpO2 90% (T90; 8.0 +/- 22.0 vs. 0.01 +/- 0.02, respectively, p < 0.05). Increasing age was associated with decreasing SpO2 (rho = -0.282, p < 0.05), obstructive apnea-hypopnea index (OAHI; rho = -0.364, p < 0.01), total arousal index (rho -0.272, p < 0.05) and respiratory arousal index (rho = -0.349, p < 0.01). Periodic limb movements in sleep (PLM) averaged 4.7 +/- 8.8/h, with a PLM index > 5/h in 5/17 children without OSA. Post- adenotonsillectomy, 8/10 children had OSA, but compared to untreated OSA-positive children they had a lower mean OAHI (4.4 +/- 5.5 vs. 8.9 +/- 12.5) and a lower T90 (1.6 +/- 4.2 vs. 9.2 +/- 24.9). CONCLUSIONS: Both OSA and PLMs were common in children with SCD. Children with Hb SS experienced more severe nocturnal oxygen desaturation than did those with Hb SC. Post-adenotonsillectomy, most children had OSA, although they experienced fewer obstructive respiratory events and less severe nocturnal oxygen desaturation than did untreated OSA-positive children.