• X-Linked Ichthyosis

Disease at a Glance

Summary
X-linked ichthyosis is a disorder in which the skin cells are produced at a normal rate but they do not separate properly at the surface of the stratum corneum (the outermost layer of the skin). This slows the rate of shedding of the skin cells, resulting in a build-up of scales. The scales of X-linked ichthyosis are often dark and usually cover only a portion of the body. Typically, the trunk and back of the neck are more likely to be affected. Scales are usually not found on the face, scalp, palms of the hands, and soles of the feet. X-linked ichthyosis mostly affects males. It is usually caused by a genetic change or deletion in the STS gene and is inherited in an X-linked recessive manner. In rare cases, the ichthyosis can be part of a genetic syndrome in which other parts of the body are affected.
Estimated Number of People with this Disease
In the U.S. there may be between

30,000 to 200,000

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
Skin Disease
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 Selected
Birth-4 weeks
Infant
1-23 months
Child
2-11 years
Adolescent
12-18 years
Adult
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:
Nervous System

9 Symptoms

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Nervous System

The nervous system is made up of the brain, spinal cord, and nerves. Common symptoms of problems in the nervous system include trouble moving, speaking, swallowing, breathing, or learning. Problems with memory, senses, or mood may also occur. Nervous system diseases are usually diagnosed and treated by neurologists.
Medical Term

Attention deficit hyperactivity disorder

Frequency: Frequent
Description

Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient.

Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient.

Childhood attention deficit/hyperactivity disorder

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

Causes

Genetic Disease

X-linked ichthyosis is a genetic disease, which means that it is caused by one or more genes not working correctly.

The following gene(s) are known to be associated with this disease: STS

  • 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)
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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:

X-linked recessive inheritance
X-linked means the gene is located on the X chromosome, one of two sex chromosomes. Genes, like chromosomes, usually come in pairs. Recessive means that when there are two copies of the responsible gene, both copies 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.

Because women have two X chromosomes, a pathogenic variant for an X-lined recessive disease generally needs to occur in both copies of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women who have a pathogenic variant in one copy of the gene, are called carriers. In rare cases, women carriers may experience mild to moderate symptoms but most have no symptoms.

A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son with the disease and a 50% (1 in 2) chance of having a daughter who is a carrier. A man with an X-linked recessive disease cannot pass on the disease to his sons, but all of his daughters will be carriers. If a male child is the first person in a family with the disease, the pathogenic variant may have been inherited from the mother or may have occurred by chance for the first time in the child (de novo).X-linked means the gene is located on the X chromosome, one of two sex chromosomes. Genes, like chromosomes, usually come in pairs. Recessive means that when there are two copies of the responsible gene, both copies 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.

Because women have two X chromosomes, a pathogenic variant for an X-lined recessive disease generally needs to occur in both copies of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women who have a pathogenic variant in one copy of the gene, are called carriers. In rare cases, women carriers may experience mild to moderate symptoms but most have no symptoms.

A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son with the disease and a 50% (1 in 2) chance of having a daughter who is a carrier. A man with an X-linked recessive disease cannot pass on the disease to his sons, but all of his daughters will be carriers. If a male child is the first person in a family with the disease, the pathogenic variant may have been inherited from the mother or may have occurred by chance for the first time in the child (de novo).
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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