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Stormorken syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Stormorken syndrome

Stormorken syndrome is a rare genetic condition affecting multiple body systems, characterized by low platelet count, muscle weakness, permanently constricted pupils, and other diverse features.

Overview

Stormorken syndrome is a rare condition that affects many body systems. Approximately a dozen cases have been reported in the medical literature.

Symptoms

Affected individuals usually have thrombocytopenia, in which there are abnormally low numbers of blood cells called platelets. Platelets are involved in normal blood clotting; a shortage of platelets typically results in easy bruising and abnormal bleeding. In addition, affected individuals often have a muscle disorder, called tubular aggregate myopathy, that leads to muscle weakness. Another feature of Stormorken syndrome is permanent constriction of the pupils of the eyes (miosis), which may be caused by abnormalities in the muscles that control the size of the pupils. Other features include lack of a functioning spleen (asplenia), scaly skin (ichthyosis), headaches, and difficulty with reading and spelling (dyslexia).

Causes

Stormorken syndrome is caused by a mutation in the STIM1 gene. The protein produced from this gene is involved in controlling the entry of positively charged calcium atoms (calcium ions) into cells. The STIM1 protein recognizes when calcium ion levels are low and stimulates the flow of ions into the cell through special channels in the cell membrane called calcium-release activated calcium (CRAC) channels. The flow of calcium ions through CRAC channels triggers signaling within cells that helps control gene activity, cell growth and division, and immune function.

The STIM1 gene mutation involved in Stormorken syndrome leads to production of a STIM1 protein that is constantly turned on (constitutively active), which means it continually stimulates calcium ion entry through CRAC channels regardless of ion levels. Researchers suggest that the abnormal ion flow in platelets causes them to break down earlier than usual, leading to thrombocytopenia and bleeding problems in people with Stormorken syndrome. It is unknown how constitutively active STIM1 leads to the other features of the disorder.

Inheritance

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from an affected parent. Other cases result from new (de novo) mutations in the gene and occur in people with no history of the disorder in their family.

Other Names

  • Stormorken-Sjaastad-Langslet syndrome
  • Thrombocytopathy, asplenia, and miosis

Frequently Asked Questions

The most critical concerns are related to the low platelet count (thrombocytopenia), which can lead to easy bruising and abnormal bleeding, and the potential for a non-functioning spleen (asplenia). Watch for signs of excessive bleeding, such as nosebleeds that won't stop, blood in urine or stool, or unusual bruising. Asplenia increases the risk of severe infections, so fevers or signs of infection should be evaluated promptly.
Management is multidisciplinary and focuses on addressing each symptom. Muscle weakness may be managed with physical therapy. The permanently constricted pupils (miosis) might require visual aids or specific lighting adjustments. Skin issues like ichthyosis (scaly skin) are typically managed with moisturizing creams and emollients. Headaches and learning difficulties like dyslexia are managed symptomatically with appropriate therapies and educational support.
Stormorken syndrome can affect a child's development due to muscle weakness, which might impact motor skills. The permanent constriction of pupils (miosis) can affect vision, especially in low light, potentially requiring adaptations for daily activities and learning. Learning difficulties like dyslexia may also be present, necessitating specialized educational support to help children reach their full potential.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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