GTR Home > Conditions/Phenotypes > Hyperekplexia hereditary

Disease characteristics

Excerpted from the GeneReview: Hyperekplexia
Hereditary hyperekplexia (HPX) is characterized by generalized stiffness immediately after birth that normalizes during the first years of life; excessive startle reflex (eye blinking and a flexor spasm of the trunk) to unexpected (particularly auditory) stimuli; and a short period of generalized stiffness following the startle response during which voluntary movements are impossible. Exaggerated head-retraction reflex (HRR) consisting of extension of the head followed by violent flexor spasms of limbs and neck muscles elicited by tapping the tip of the nose is observed in most children. Other findings include periodic limb movements in sleep (PLMS) and hypnagogic (occurring when falling asleep) myoclonus. Sudden infant death (SIDS) has been reported. Intellect is usually normal; mild intellectual disability may occur.

Available tests

33 tests are in the database for this condition. Compare labs offering these tests.

Check Associated genes and Related conditions for additional relevant tests.

Associated genes

Clinical features

Help
  • Apnea
  • Umbilical hernia
  • Hypertonia
  • Frequent falls
  • Hypokinesia
  • Seizure
  • Aspiration
  • Inguinal hernia
  • Myoclonus
  • Exaggerated startle response
  • Hip dislocation
Show all (11)

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Write to the Help Desk