Overview
Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome (HPFH-SS) is a compound heterozygous condition in which an individual inherits one sickle hemoglobin (HbS) gene and one hereditary persistence of fetal hemoglobin (HPFH) gene. HPFH is characterized by continued production of fetal hemoglobin (HbF) into adulthood at significantly elevated levels, typically ranging from 15% to 30% or higher. Because fetal hemoglobin inhibits the polymerization of sickle hemoglobin, individuals with this syndrome generally experience a much milder clinical course compared to homozygous sickle cell disease (HbSS). The condition primarily affects the hematologic system, with red blood cells carrying a mixture of HbS and HbF. Clinically, patients with HPFH-sickle cell disease syndrome tend to have fewer or no vaso-occlusive crises, reduced hemolytic anemia, and a lower incidence of the severe complications typically associated with sickle cell disease, such as acute chest syndrome, stroke, and organ damage. Many individuals are essentially asymptomatic or have only mild anemia. Laboratory findings typically show elevated HbF levels with a relatively even distribution of fetal hemoglobin across red blood cells (pancellular distribution), which is a hallmark of HPFH. Hemoglobin levels tend to be higher and reticulocyte counts lower than in classic sickle cell disease. Due to the generally benign clinical course, many patients with HPFH-sickle cell disease syndrome require minimal or no specific treatment. Management focuses on monitoring for potential complications and providing standard sickle cell disease supportive care when needed, including hydration, pain management, and infection prevention. The favorable prognosis associated with high HbF levels in this condition has been a key observation driving research into HbF-inducing therapies, such as hydroxyurea and newer gene therapy approaches, for the treatment of more severe forms of sickle cell disease.
Clinical phenotype terms— hover any for plain English:
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Childhood
Begins in childhood, roughly ages 1 to 12
FDA & Trial Timeline
10 eventsBeijing Anzhen Hospital
University of Illinois at Chicago — PHASE2
University of Rochester — PHASE4
University Department of Geriatric Medicine FELIX PLATTER — NA
University of Rochester — NA
Tampere Heart Hospital
Children's Hospital Medical Center, Cincinnati — PHASE4
Casa di Cura IGEA
Central Hospital, Nancy, France — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
1 availableSiklos
To reduce the frequency of painful crises and to reduce the need for blood transfusions in pediatric patients, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painf…
To reduce the frequency of painful crises and to reduce the need for blood transfusions in pediatric patients, 2 years of age and older, with sickle cell anemia with recurrent moderate to severe painful crises
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Financial Resources
1 resourcesTravel Grants
No travel grants are currently matched to Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome.
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Start the conversation →Latest news about Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
Disease timeline:
New recruiting trial: Lombard Cohort of Brain Health Services
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
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A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
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A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
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A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
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A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
New recruiting trial: Attentional Mechanisms in SCD
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
New recruiting trial: HeartStart HS1 Defibrillator* Event Registry
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
New recruiting trial: Personalized Digital Training for COGnitive FITness in Mild Cognitive Impairment
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
New recruiting trial: HS Students Mandatory Universal Student Instruction in CPR Appraised Learning- Is the Mandate Working?
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
New recruiting trial: Developing a Peer Support Intervention for Depression in SCD
A new clinical trial is recruiting patients for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Common questions about Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome
What is Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome?
Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome (HPFH-SS) is a compound heterozygous condition in which an individual inherits one sickle hemoglobin (HbS) gene and one hereditary persistence of fetal hemoglobin (HPFH) gene. HPFH is characterized by continued production of fetal hemoglobin (HbF) into adulthood at significantly elevated levels, typically ranging from 15% to 30% or higher. Because fetal hemoglobin inhibits the polymerization of sickle hemoglobin, individuals with this syndrome generally experience a much milder clinical course compared to homozygous sickle
How is Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome inherited?
Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome typically begin?
Typical onset of Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome is childhood. Age of onset can vary across affected individuals.
Are there clinical trials for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome?
Yes — 1 recruiting clinical trial is currently listed for Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome?
9 specialists and care centers treating Hereditary persistence of fetal hemoglobin-sickle cell disease syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.