HYPEREKPLEXIA, HEREDITARY 1

General Information (adopted from Orphanet):

Synonyms, Signs: STARTLE DISEASE, FAMILIAL
KOK DISEASE
STIFF-MAN SYNDROME, CONGENITAL
STIFF-BABY SYNDROME
EXAGGERATED STARTLE REACTION
STARTLE REACTION, EXAGGERATED
STIFF-PERSON SYNDROME, CONGENITAL
HKPX1
STHE
Number of Symptoms 16
OrphanetNr:
OMIM Id: 149400
ICD-10:
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Autosomal dominant inheritance
Autosomal recessive inheritance
[Omim]
Age of onset: Infantile onset
[Omim]

Disease classification (adopted from Orphanet):

Parent Diseases: No data available.

Symptom Information: Sort by abundance 

1
(HPO:0001336) Myoclonus 115 / 7739
2
(HPO:0002267) Exaggerated startle response 42 / 7739
3
(HPO:0001276) Hypertonia 317 / 7739
4
(HPO:0002359) Frequent falls 24 / 7739
5
(HPO:0002827) Hip dislocation 94 / 7739
6
(HPO:0001537) Umbilical hernia 206 / 7739
7
(HPO:0000023) Inguinal hernia 181 / 7739
8
(OMIM) Episodic generalized skeletal muscle contractions 1 / 7739
9
(OMIM) EMG shows continuous motor unit firing at rest 1 / 7739
10
(OMIM) Hypokinesia in infancy 1 / 7739
11
(OMIM) Frightened expression 1 / 7739
12
(OMIM) Alert affect 1 / 7739
13
(OMIM) Hyperactive brainstem reflexes (head retraction, palmomental, snout) 1 / 7739
14
(OMIM) EEG during episodes shows desynchronization 1 / 7739
15
(OMIM) Tense affect 1 / 7739
16
(OMIM) Nocturnal seizures 3 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Hyperekplexia is an early-onset neurologic disorder characterized by an exaggerated startle response to sudden, unexpected auditory or tactile stimuli. Affected individuals have brief episodes of intense, generalized hypertonia in response to stimulation. Neonates may have prolonged periods of ...
Clinical Description OMIM Ryan et al. (1992) suggested that this disorder was first described by Kirstein and Silfverskiold (1958), who reported a 'family with emotionally precipitated drop seizures.'

Suhren et al. (1966) described a family in which 25 persons ...

Molecular genetics OMIM In affected members of 4 families with autosomal dominant hyperekplexia, 2 of whom were reported by Ryan et al. (1992), Shiang et al. (1993) identified 2 heterozygous mutations in the GLRA1 gene (138491.0001-138491.0002).

In a sporadic ...