• Sea-Blue Histiocytosis

Disease at a Glance

Summary
Sea-Blue histiocytosis, also known as inherited lipemic splenomegaly, is an extremely rare condition characterized by elevated triglyceride levels (hypertriglyceridemia) and an enlarged spleen (splenomegaly). The disorder is so named because certain white blood cells, known as histiocytes, appear bright blue when stained and viewed under the microscope. Additional signs and symptoms may include a low platelet count (thrombocytopenia), liver function abnormalities, and heart disease. It is one of a group of related fat (lipid) disorders caused by certain changes in the APOE gene. The genetic change associated with this condition is inherited in an autosomal dominant manner though other factors, such as a patient's gender, the patient's lipid levels, and the genetic makeup of the other APOE gene may play a role in how the condition is expressed.
Estimated Number of People with this Disease
In the U.S., this disease is estimated to be less than

1,000

What Information Does GARD Have For This Disease?

Many rare diseases have limited information. Currently GARD is able to provide the following information for this disease:

*Data may be currently unavailable to GARD at this time.
Categories
When do symptoms of this disease begin?
The most common ages for symptoms of a disease to begin is called age of onset. Age of onset can vary for different diseases and may be used by a doctor to determine the diagnosis. For some diseases, symptoms may begin in a single age range or several age ranges. For other diseases, symptoms may begin any time during a person's life.
Prenatal
Before Birth
Newborn
Birth-4 weeks
Infant
1-23 months
Child
2-11 years
Adolescent Selected
12-18 years
Adult Selected
19-65 years
Older Adult
65+ years
The common ages for symptoms to begin in this disease are shown above by the colored icon(s).
This information comes from Orphanet

Symptoms

These symptoms may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list does not include every symptom.
This disease might cause these symptoms:
Blood and Blood-Forming Tissue

13 Symptoms

Tile View
List View
Tile View
List View

Blood and Blood-Forming Tissue

The blood and blood-forming tissue includes plasma, red blood cells, white blood cells, platelets, and bone marrow. Common symptoms of problems with the blood or blood forming tissue include fatigue, weakness, shortness of breath, fever, abnormal bleeding, headache, or bruising easily. Diseases of the blood may be diagnosed and treated by a hematologist.
Medical Term

Abnormal bleeding

Frequency: Very frequent (80-99%)
Description

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

Synonym

Hemorrhagic diathesis

Hemorrhagic diathesis

13 Symptoms
This information comes from the Human Phenotype Ontology (HPO)

Causes

Genetic Disease

Sea-Blue histiocytosis is a genetic disease, which means that it is caused by one or more genes not working correctly.

Disease causing variants in the following gene(s) are known to cause this disease: APOE

  • Questions:

Questions:

What is a gene?
Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins. 

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What is a gene? (MedlinePlus) ; What's a Gene? (NHGRI) ; What are proteins and what do they do? (MedlinePlus)Genes are part of our DNA, the basic genetic material found in each of our body's cells. Cells are the building blocks of all living things and specialized cells form our body's organs and tissues. DNA is found in the nucleus of a cell and, in humans, is packaged into 23 pairs of chromosomes with the help of special proteins. 

Each gene performs a different job in our cells. Some genes serve as the instructions to make proteins. Proteins are needed for the structure, function, and regulation of the body's cells, tissues, and organs. Some genes can turn other genes on or off. Others make RNA molecules that are involved in chemical reactions in the body.

Sources to Learn More: What is a gene? (MedlinePlus) ; What's a Gene? (NHGRI) ; What are proteins and what do they do? (MedlinePlus)
Read More
Inheritance

All individuals inherit two copies of most genes. The number of copies of a gene that need to have a disease-causing variant affects the way a disease is inherited. This disease is inherited in the following pattern(s):

Questions:

Autosomal dominant inheritance
Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Dominant means that only one copy of the responsible gene (causal gene) must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

In some cases, a person inherits the pathogenic variant from a parent who has the genetic disease. In other cases, the disease occurs because of a new pathogenic variant (de novo) in the causal gene and there is no family history of the disease.

Each child of an individual with an autosomal dominant disease has a 50% (1 in 2) chance of inheriting the variant and the disease. Typically, children who inherit a dominant variant will have the disease, but they may be more or less severely impacted than their parent. Sometimes a person may have a pathogenic variant for an autosomal dominant disease and show no signs or symptoms of the disease.Autosomal means the gene is located on any chromosome except the X or Y chromosomes (sex chromosomes). Genes, like chromosomes, usually come in pairs. Dominant means that only one copy of the responsible gene (causal gene) must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.

In some cases, a person inherits the pathogenic variant from a parent who has the genetic disease. In other cases, the disease occurs because of a new pathogenic variant (de novo) in the causal gene and there is no family history of the disease.

Each child of an individual with an autosomal dominant disease has a 50% (1 in 2) chance of inheriting the variant and the disease. Typically, children who inherit a dominant variant will have the disease, but they may be more or less severely impacted than their parent. Sometimes a person may have a pathogenic variant for an autosomal dominant disease and show no signs or symptoms of the disease.
Read More
Next Steps

Talking with the Medical Team

Good communication between the patient, family, and medical team can lead to an accurate diagnosis. In addition, health care decisions can be made together which improves the patient’s well-being and quality of life.

Describing Symptoms

Describe details about the symptoms. Because there may be many different causes for a single symptom, it is best not to make a conclusion about the diagnosis. The detailed descriptions help the medical provider determine the correct diagnosis.

To help describe a symptom:

  • Use a smartphone or a notebook to record each symptom before the appointment
  • Describe each symptom by answering the following questions:
    • When did the symptom start?
    • How often does it happen?
    • Does anything make it better or worse?
  • Tell the medical team whether any symptoms affect daily activities

Preparing for the First Visit

Working with a medical team to find a diagnosis can be a long process that will require more than one appointment. Make better health decisions by being prepared for the first visit with each member of the medical team.

    Make informed decisions about health care: 
    • Prepare a list of questions and concerns before the appointment
    • List the most important questions first, not all questions may be answered in the first visit
    • Ask questions about symptoms, possible diagnoses, tests, and treatment options
    For future appointments:
    • Discuss what was not addressed at the last visit
    • Discuss changes in the quality of life for the patient, family, and caregivers
    • Discuss health goals and other issues in the patient’s and family’s life that may affect the health care decisions
    Take notes during the appointments to help remember what was discussed.

    Next: Diagnosis & Treatment

    Last Updated: Nov. 8, 2021