Hereditary hyperekplexia

Hyperekplexia, HPX, familial hyperekplexia, startle syndrome, startle disease, exaggerated surprise

What is hereditary hyperekplexia?

Hereditary hyperekplexia is a rare genetic neurological condition that causes jerky movement, exaggerated startle reactions and muscle rigidity.

These reactions can be triggered by a variety of stimuli, including unexpected sounds, lights, or movements.

Some people with hyperekplexia are diagnosed as babies, while others do not receive a diagnosis until adulthood.

There is no cure for this condition, however there are treatments available.

What is the cause of hyperekplexia?

Hyperekplexia is genetic, meaning it is caused by a mutation to a certain gene or genes. In the case of hyperekplexia, multiple genes are found to be mutated.

This means that people with a family history of the condition may be at an increased risk.

If you or someone you know is experiencing symptoms resembling hyperekplexia, it is recommended to consult with a doctor for a proper diagnosis – via genetic blood testing – and appropriate management.

What are the symptoms of hyperekplexia?

Hyperekplexia manifests as a highly diverse condition, with the severity varying across the different gene mutations.

The symptoms of hyperekplexia can include:

  • Extreme muscle rigidity
  • Jerking movements
  • Extreme muscle tension and stiffness
  • Exaggerated startle reactions
  • Unstable walking and uneven gait
  • Arching of the head and neck
  • Falling without loss of consciousness
  • Inability to control movements in the body
  • Cognitive difficulties such as developmental delays and memory problems
  • Apnoea (stopping breathing)

Are you affected by hyperekplexia?

If you’re affected by hyperekplexia, The Brain Charity can support you.

We are the only charity in the UK to be here for every one of the more than 600 different neurological conditions in existence. Individually, many are rare, but combined, they affect 1 in 6 people.

We provide practical help on all aspects of living with hyperekplexia, emotional support such as counselling, phone befriending and group therapy and social activities to people with hyperekplexia and their family, friends and carers from all over the UK from our centre in Liverpool.

Looking to talk to someone?

Woman smiling, making eye contact and holding the hand of another woman to comfort her

Phone us

Contact The Brain Charity now

Our friendly Information & Advice Officers are here to help. We endeavour to respond to all enquiries within 10 working days.

0151 298 2999

Looking to talk to someone?

  • Please tell us which neurological condition you are affected by and what you need support with.

Caring for someone with hyperekplexia

We support carers, friends and family too

Are you a carer for or relative of someone with hyperekplexia? It’s just as important for you to look after your own physical and mental wellbeing too.

The Brain Charity provides free support for carers, friends and family of people with any form of neurological condition, including hyperekplexia, from anywhere in the UK.

We also run an additional carers advocacy service for all carers in Liverpool, regardless of which type of condition the person they care for has.

You don’t need to be a formal or registered carer

We can help you even if you don’t view yourself as a formal carer or claim Carer’s Allowance. Find out some of the ways we support carers below.

Other resources

The Brain Charity's library

The Brain Charity’s library has a range of resources on hyperekplexia and on many other neurological conditions

Visit our library to read:

  • Neurology (Oxford Core Texts) by M. Donaghy, 2005

or search the catalogue online here.

Support groups

The Hyperekplexia Society

The Hyperekplexia Society is an online global Facebook support group for anyone who has hyperekplexia, knows someone that has, or is the parent of a child with hyperekplexia to share their experiences and concerns.

Click here to join the group.

Other charities

Stiff person syndrome UK