BACKGROUND: Skull infarction is an uncommonly reported complication of sickle cell disease. We aimed to characterize the clinical and imaging features of skull infarction in pediatric patients with sickle cell disease.
METHODS: We searched the PubMed database for case reports on skull bone infarction in pediatric patients with sickle cell disease. Out of 67 records retrieved, 15 met inclusion criteria, and a 16th case reported by the senior author was included. We extracted and analyzed clinical and imaging data.
RESULTS: The most common symptom at onset was headache (88%). Bilateral skull infarction (50%) and parietal bone involvement (82%) were frequent imaging findings. Epidural hematoma developed in 65% of the cases, 30% of patients required drainage, and exchange infusion was reported in 18%. No fatal outcomes were reported.
CONCLUSIONS: Skull infarction is a potentially severe complication of sickle cell disease presenting unique clinical challenges. Acute headaches should raise suspicion for this condition and may require additional investigation.

OBJECTIVE: Sickle cell disease (SCD) affects all organ systems and is characterized by numerous acute and chronic complications and comorbidities. Standardized codes are needed for complications/comorbidities used in real-world evidence (RWE) studies that rely on administrative and medical coding. This systematic literature review was conducted to produce a comprehensive list of complications/comorbidities associated with SCD, along with their diagnosis codes used in RWE studies.
METHODS: A search in MEDLINE and Embase identified studies published from 2016 to 2023. Studies were included if they were conducted in US SCD populations and reported complications/comorbidities and respective International Classification of Diseases, Clinical Modification (ICD-CM) codes. All identified complications/comorbidities and codes were reviewed by a certified medical coding expert and hematologist.
RESULTS: Of 1851 identified studies, 39 studies were included. The most reported complications/comorbidities were stroke, acute chest syndrome, pulmonary embolism, venous thromboembolism, and vaso-occlusive crisis. Most of the studies used ICD-9-CM codes (n = 21), while some studies used ICD-10-CM codes (n = 3) or both (n = 15), depending on the study period. Most codes reported in literature were heterogeneous across complications/comorbidities. The medical coding expert and hematologist recommended modifications for several conditions.
CONCLUSIONS: While many studies we identified did not report their codes and were excluded from this review, the studies with codes exhibited diverse coding definitions. By providing a standardized set of diagnosis codes that were reported by studies and reviewed by a coding expert and hematologist, our review can serve as a foundation for accurately identifying complications/comorbidities in future research, and may reduce heterogeneity, enhance transparency, and improve reproducibility. Future efforts focused on validating these code lists are needed.

Background/Objectives: Sickle cell disease (SCD) impacts about 100,000 people in the US. SCD increases the risk of cholelithiasis and microvascular ischemia, which could increase the risk of acute pancreatitis (AP). Abdominal pain is a common presenting symptom of AP and sickle cell vaso-occlusive crisis. The purpose of our systematic review is to estimate the prevalence and determine the severity of AP in individuals with SCD compared to the general population. Methods: Multiple electronic databases were searched. We included studies that included children and adults (population) and addressed the association of SCD (exposure) with AP (outcome) compared to the same population without SCD (control). Two authors screened titles and abstracts independently, and data were abstracted in duplication from included studies. We registered this protocol in PROSPERO-CRD42023422397. Results: Out of 296 studies screened from multiple electronic databases, we identified 33 studies. These studies included 17 case reports, one case series, and 15 retrospective cohort studies, and 18 studies included children. Eight of the AP case reports were in patients with HbSS genotype, two with sickle beta thalassemia, and one with HbSoArab, and in six case reports, a genotype was not specified. Complications were reported in 11 cases-respiratory complication (in at least four cases), splenic complications (three cases), pancreatic pseudocyst (two cases) and death from AP (one case). Of the four AP cases in the case series, three had HbSS genotype, and two cases had complications and severe pancreatitis. AP prevalence in SCD was estimated to be 2% and 7% in two retrospective studies, but they lacked a comparison group. In retrospective studies that evaluated the etiology of AP in children, biliary disease caused mostly by SCD was present in approximately 12% and 34%, respectively. Conclusions: Data on the prevalence of AP in individuals with SCD are limited. Prospectively designed studies aiming to proactively evaluate AP in individuals with SCD who present with abdominal pain are needed to improve timely diagnosis of AP in SCD and outcomes.

This study examined sickle cell disease (SCD) in Saudi Arabia. A systematic search of relevant databases was conducted to identify studies investigating SCD in the Saudi population. Studies were then screened based on predefined criteria and critically appraised for methodological quality. Data was extracted and synthesized to provide an overall picture of the SCD burden in Saudi Arabia. The most commonly reported complications were vaso-occlusive crises (VOC), acute chest syndrome (ACS), acute painful crisis, splenic sequestration, osteomyelitis, aplastic crisis, hemolytic crisis, serious bacterial infections, chronic vascular occlusion (CVO), depression, sickle cell nephropathy (SCN), obstructive sleep apnea (OSA), and renal complications. Reduced blood levels of antioxidant trace elements (Cu, Zn, and Se) may encourage oxidative stress, which in turn may contribute to the pathophysiology of SCD. Infections and ACS were common among young children (<7 years) while pain attacks were common in older children (>7 years). The high rate of hospitalizations among SCD patients highlights the need for better management strategies. Future research should focus on understanding the underlying causes of SCD complications and developing new ways to control them.

Due to the significant morbidity and mortality of hemoglobinopathies, curative options have long been pursued. The overall goal of gene therapy is to modify a patient\'s own hematopoietic stem cells to overcome the deleterious effects of the underlying genetic defect by gene addition, gene editing, or gene silencing. Gene addition incorporates genes with superior function than the abnormal gene; gene editing takes advantage of molecular tools such as zinc finger proteins, Transcription Activator-Like Effector Nucleases and Clustered Regularly Interspaced Short Palindromic Repeats coupled with Cas9 proteins (CRISPR-Cas9) which allow for sequence-specific breaks in DNA that disrupt gene function; and gene silencing suppresses gene expression by interference with mRNA transcription/protein translation or epigenetic modification. The majority of gene therapy strategies for hemoglobinopathies have targeted erythroid-specific BCL11A, a major regulator of fetal hemoglobin repression at the gamma-globin locus, in the normal fetal-to-adult hemoglobin switch that occurs shortly after birth. Other goals have involved the incorporation of anti-sickling globins, such as βT87Q or βAS3. Landmark clinical trials of gene therapy in transfusion-dependent thalassemia and sickle cell disease have shown remarkable efficacy and acceptable safety and culminated in recent regulatory approvals of gene therapy for both diseases in Europe and the United States.

Sickle cell disease (SCD) is associated with substantial morbidity and early mortality in afflicted adults. Cardiopulmonary complications that occur at increased frequency in SCD such as pulmonary embolism, pulmonary arterial hypertension, and acute chest syndrome can acutely worsen right ventricular function and lead to cardiogenic shock. Mechanical circulatory support including venoarterial extracorporeal membrane oxygenation (VA ECMO) is being increasingly utilized to treat hemodynamic collapse in various patient populations. However, a paucity of literature exists to guide the use of mechanical circulatory support in adults with SCD where disease-related sequela and unique hematologic aspects of this disorder may complicate extracorporeal therapy and must be understood. Here, we review the literature and describe three cases of adult patients with SCD who developed cardiogenic shock from acute decompensated right heart failure and were treated clinically with VA ECMO. Using an in vitro ECMO system, we investigate a potential increased risk of systemic fat emboli in patients with SCD who may be experiencing vaso-occlusive events with bone marrow involvement given the high-volume shunting of blood from venous to arterial systems with VA ECMO. The purpose of this study is to describe available extracorporeal life support experiences, review potential complications, and discuss the special considerations needed to further our understanding of the utility of VA ECMO in those with SCD.

Background: Microvascular occlusions caused by sickle-shaped erythrocytes in patients with sickle cell disease (SCD) can lead to increased intraoperative and postoperative complications during total hip arthroplasty (THA). This systematic review and meta-analysis aimed to estimate the overall rate of complications following THA in patients with SCD and to identify the predictors of these complications including the surgical approach. Methods: The search was conducted across the grey literature, Google Scholar, and seven databases: Scopus, MEDLINE Central/PubMed, ProQuest, SciELO, SAGE, and Web of Science. All observational studies reporting the proportional THA complications in SCD were included. The Newcastle-Ottawa Scale quality assessment tool was used to assess the quality of the studies. The random effect model was applied to estimate the pooled outcomes. A sub-group analysis for the different approaches was performed. A sensitivity analysis and meta-regression were used to explain heterogeneity and to identify the THA complication predictors. Results: Of 3230 citations, only 23 studies were eligible for the meta-analysis. The pooled proportion of total primary THA complications in patients with SCD was 42% (95% CI: 30-56%, I2 = 95%). The sub-group analysis highlighted the anterolateral approach as the approach accompanied with the least complications. The meta-regression revealed that the anterolateral approach decreases the complications significantly, -28.67 (95%CI, -56.45--0.88, p = 0.044), while the number of hips increased the complications by 0.43 (95%CI, 0.30-0.57, p < 0.001). Male gender, age, lateral approach, and HbSS non-significantly affect the THA complications in SCD 52.05, 0.18, 6.06, and 55.78, respectively. The pooled proportions for an SCD crisis 9% (95%CI, 5-14%, I2 = 61%), dislocation 4% (95%CI: 2-7%, I2 = 66%), aseptic loosening 12% (95%CI, 7-20%, I2 = 91%), revision 6% (3-11, I2 = 92%), heterotopic ossification 12% (95%CI, 3-35%, I2 = 95%), and prosthetic joint infection (PJI) 6% (95%CI, 3-11%, I2 = 92%). The most fitted model of meta-regression illustrated that HbSS significantly increases PJI, 0.05 (95%CI: 0.02-0.08, p = 0.009), and male gender and age non-significantly increase PJI, 2.28 (95%CI: -4.99-13.56, p = 0.311) and 0.001 (95%CI: -0.27-0.27, p = 0.990), respectively. Meanwhile, the anterolateral, lateral, and posterior approaches non-significantly decrease PJI, -3.55, -0.92, and -1.27, respectively. The pooled proportion for a sickle cell disease crisis after revision was 16% (95%CI: 6-36%, I2 = 0) and for aseptic loosening after revision, it was 24% (95%CI: 12-43%, I2 = 0). Conclusions: This study revealed the high rate of complications in patients with SCD and highlighted that the anterolateral approach was associated with the lowest rate of complications. Furthermore, this study illustrated that homozygous (HbSS) individuals are more susceptible to prosthetic joint infection.

A considerable fraction of population in the world suffers from rare diseases. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and its related Cas proteins offer a modern form of curative gene therapy for treating the rare diseases. Hereditary transthyretin amyloidosis, hereditary angioedema, duchenne muscular dystrophy and Rett syndrome are a few examples of such rare diseases. CRISPR/Cas9, for example, has been used in the treatment of β-thalassemia and sickle cell disease (Frangoul et al., 2021; Pavani et al., 2021) [1,2]. Neurological diseases such as Huntington\'s have also been focused in some studies involving CRISPR/Cas (Yang et al., 2017; Yan et al., 2023) [3,4]. Delivery of these biologicals via vector and non vector mediated methods depends on the type of target cells, characteristics of expression, time duration of expression, size of foreign genetic material etc. For instance, retroviruses find their applicability in case of ex vivo delivery in somatic cells due to their ability to integrate in the host genome. These have been successfully used in gene therapy involving X-SCID patients although, incidence of inappropriate activation has been reported. On the other hand, ex vivo gene therapy for β-thalassemia involved use of BB305 lentiviral vector for high level expression of CRISPR biological in HSCs. The efficacy and safety of these biologicals will decide their future application as efficient genome editing tools as they go forward in further stages of human clinical trials. This review focuses on CRISPR/Cas based therapies which are at various stages of clinical trials for treatment of rare diseases and the constraints and ethical issues associated with them.

OBJECTIVE: To delineate the natural history of splenic complications other than loss of splenic function in children with sickle cell disease (SCD), we performed a retrospective chart review of patients with SCD treated at the Texas Children\'s Hospital.
METHODS: We determined the dates of diagnoses of splenic complications, the number of acute splenic sequestration crises (ASSC), and hydroxyurea treatment in pediatric patients with SCD. We also examined the association of hydroxyurea therapy with the onset and severity of ASSC.
RESULTS: The cumulative prevalence of splenic complications was 24.7% for splenomegaly, 24.2% for ASSC, 9.6% for hypersplenism, and 5.6% for splenectomy. The cumulative prevalence of splenic complications was highest in patients with hemoglobin Sβ0 (69.2%), intermediate in hemoglobin SS (33.3%), low in hemoglobin SC (9.0%), and non-existent in hemoglobin Sβ+. The overall event rate of ASSC was 8.3 per 100 patient-years. The event-rate was 28.4 for hemoglobin Sβ0, 10.9 for hemoglobin SS, and 3.5 for hemoglobin SC. Patients with hemoglobin SS and hemoglobin Sβ0 on hydroxyurea therapy had a significantly higher occurrence of ASSC than those who were not, with event rates of 14.2 and 3.1, respectively. The event rate was also higher for children who started hydroxyurea before age 2 years than for those who started after this age (19.8 and 9.2, respectively).
CONCLUSIONS: The prevalence and severity of splenic problems vary widely between different sickle cell genotypes, with hemoglobin Sβ0 having the most severe complications. Hydroxyurea therapy is associated with increased incidence of ASSC, particularly when initiated before 2 years of age.

Sickle cell disease (SCD) is an autosomal recessive genetic disorder characterized by the abnormal formation of sickle hemoglobin (HbS). Under conditions of deoxygenation, HbS undergoes polymerization, resulting in microvascular occlusion, tissue hypoxia, and infarction. The elevated mortality rate associated with SCD is primarily attributed to complications such as sepsis, acute chest syndrome, stroke, acute multiorgan failure, and pulmonary hypertension. Despite advancements in awareness and treatments, preventing mortality in young individuals with SCD remains a formidable challenge. In an effort to shed light on these challenges, we present a case of unexpected death associated with SCD to emphasize the pressing need for continued research and intervention strategies to improve patient outcomes.