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HSD10 disease
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Conditions

HSD10 disease

HSD10 disease is a rare disorder primarily affecting the nervous system, vision, and heart, with males typically experiencing more severe symptoms and developmental regression than females.

Overview

HSD10 disease is a disorder that affects the nervous system, vision, and heart. It is typically more severe in males than in females. Most affected males have a form of HSD10 disease in which early development seems normal, followed by a stage in which affected individuals rapidly lose skills they have acquired. This developmental regression often occurs between the ages of 1 and 2 and results in severe intellectual disability and loss of communication skills and motor skills such as sitting, standing, and walking. This form of the disorder is referred to as the infantile type. Less commonly, affected males have severe neurological problems from birth and never develop motor skills. This form is called the neonatal type. Males with the infantile or neonatal type frequently have weak muscle tone (hypotonia), recurrent seizures (epilepsy), and vision loss that gradually gets worse. Weakening of the heart muscle (cardiomyopathy) also occurs and is a common cause of death in males with severe HSD10 disease. Many affected males do not survive beyond early childhood.

Females with HSD10 disease may have developmental delay, learning problems, or intellectual disability, but they do not experience developmental regression. Some affected females have additional features of this condition, such as epilepsy, movement problems, and hearing loss. Affected females appear to have a normal life expectancy.

Frequency

HSD10 disease is a very rare disorder. Its prevalence is less than 1 in 1 million people.

Causes

HSD10 disease is caused by mutations in the HSD17B10 gene, which provides instructions for making the HSD10 protein. This protein is located within mitochondria, the energy-producing centers inside cells, where it is involved in the protein synthesis. While most protein synthesis occurs in the fluid surrounding the nucleus (cytoplasm), a few proteins are synthesized in the mitochondria.

During protein synthesis, in either the mitochondria or the cytoplasm, molecules called transfer RNAs (tRNAs) help assemble protein building blocks (amino acids) into chains that form proteins. The HSD10 protein is part of a group of proteins (a complex) that is involved in making functional mitochondrial tRNA molecules, which aid in the synthesis of mitochondrial proteins. Normal mitochondrial protein production is essential for the formation of the groups of proteins that convert the energy from food into a form cells can use.

The HSD17B10 gene mutations that cause HSD10 disease reduce the amount of HSD10 protein in cells, impair their structure or function, or both, which leads to a deficiency of the functional complex in which it plays a part. This deficiency impairs the production of mitochondrial tRNAs. Without enough tRNAs, the mitochondrial synthesis of proteins involved in cellular energy production is reduced. A shortage of these proteins results in insufficient energy production in cells of the brain, eyes, and heart, leading to the characteristic features of HSD10 disease.

Inheritance

This condition is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males, who have only one X chromosome, a mutation in the only copy of the gene in each cell is sufficient to cause the condition. In females, who have two copies of the X chromosome, one altered copy of the gene in each cell can lead to less severe features of the condition or may cause no signs or symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Other Names for This Condition

  • 17β-hydroxysteroid dehydrogenase type 10 deficiency
  • 2-methyl-3-hydroxybutyric aciduria
  • 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency
  • 2M3HBA
  • 3-hydroxy-2-methylbutyryl-CoA dehydrogenase deficiency
  • 3H2MBD deficiency
  • HSD10 deficiency
  • Hydroxyacyl-CoA dehydrogenase II deficiency
  • MHBD deficiency

Frequently Asked Questions

In the infantile type of HSD10 disease, early development often appears normal, with the first signs emerging between ages 1 and 2. Key red flags include a sudden loss of previously acquired skills, such as stopping walking or speaking, accompanied by increasing muscle weakness (hypotonia) and the onset of seizures. If a child who was previously meeting milestones begins to regress, particularly if accompanied by visual changes or heart palpitations, immediate evaluation by a pediatric neurologist and geneticist is recommended.
Cardiomyopathy, which is the weakening of the heart muscle, is a serious and common complication in males with severe forms of the disease and is a leading cause of mortality. Regular monitoring through echocardiograms is critical to detect early signs of heart failure. Treatment may involve standard heart failure medications, and in severe cases, advanced interventions such as heart transplantation may be considered.
HSD10 disease is an X-linked disorder caused by mutations in the HSD10 gene. Males have only one X chromosome, so a single mutation leads to a complete lack of functional protein, resulting in severe neurological decline. Females have two X chromosomes; due to X-inactivation, they retain some functional protein from the unaffected X chromosome, which often protects them from the severe regression seen in males, though they may still experience milder symptoms like learning disabilities or epilepsy.
There is currently no cure for HSD10 disease. Management is supportive and focuses on addressing specific symptoms. This includes anti-seizure medications for epilepsy, physical and occupational therapy to maintain mobility and function, speech therapy for communication, and nutritional support. For males with the infantile type, the focus is often on palliative care and managing complications such as seizures and heart failure to improve quality of life.
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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