Monomelic amyotrophy

General Information (adopted from Orphanet):

Synonyms, Signs: SPINAL MUSCULAR ATROPHY, JUVENILE, NONPROGRESSIVE
JMADUE
Juvenile muscular atrophy of distal upper extremity
hirayama disease
Juvenile muscular atrophy of the distal upper limb
Benign focal amyotrophy
Number of Symptoms 35
OrphanetNr: 65684
OMIM Id: 602440
ICD-10: G12.8
UMLs: C1865384
MeSH: C538253
MedDRA: 10069681
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: No data available.
Inheritance: Unknown
[Orphanet]
Age of onset: Adolescent
Adult
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Acquired motor neuron disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
 (HPO:0001337) Tremor Occasional [Orphanet] 200 / 7739
2
 (HPO:0002380) Fasciculations 42 / 7739
3
 (HPO:0004305) Involuntary movements Occasional [Orphanet] 50 / 7739
4
 (HPO:0003134) Abnormality of peripheral nerve conduction Frequent [Orphanet] 38 / 7739
5
 (HPO:0100022) Abnormality of movement Occasional [Orphanet] 129 / 7739
6
 (HPO:0003468) Abnormality of the vertebrae Frequent [Orphanet] 77 / 7739
7
 (HPO:0002817) Abnormality of the upper limb Very frequent [Orphanet] 25 / 7739
8
 (HPO:0001063) Acrocyanosis Frequent [Orphanet] 56 / 7739
9
 (HPO:0002715) Abnormality of the immune system Occasional [Orphanet] 46 / 7739
10
 (HPO:0003484) Upper limb muscle weakness 19 / 7739
11
 (HPO:0003445) EMG: neuropathic changes 21 / 7739
12
 (HPO:0007181) Interosseus muscle atrophy 3 / 7739
13
 (HPO:0003202) Skeletal muscle atrophy Very frequent [Orphanet] 281 / 7739
14
 (HPO:0001324) Muscle weakness Very frequent [Orphanet] 859 / 7739
15
 (HPO:0003457) EMG abnormality Very frequent [Orphanet] 78 / 7739
16
 (OMIM) Normal sensation 2 / 7739
17
 (HPO:0040065) Abnormal morphology of bones of the upper limbs Very frequent [Orphanet] 25 / 7739
18
 (OMIM) EMG shows fibrillations 1 / 7739
19
 (OMIM) Symptoms are progressive for a few years, and then become stationary 1 / 7739
20
 (OMIM) Muscle atrophy restricted to the upper limb 1 / 7739
21
 (OMIM) Muscle weakness restricted to the upper limb 1 / 7739
22
 (HPO:0003745) Sporadic 131 / 7739
23
 (OMIM) Amyotrophy affects C5 to T1 myotomes 1 / 7739
24
 (OMIM) Minipolymyoclonus 1 / 7739
25
 (OMIM) Usually a unilateral disorder 1 / 7739
26
 (OMIM) EMG shows fasciculations 1 / 7739
27
 (OMIM) A subset of patients have aggravation on cold exposure ('cold paresis') 1 / 7739
28
 (MedDRA:10029176) Nerve conduction studies normal 1 / 7739
29
 (OMIM) Interosseus muscles involved 1 / 7739
30
 (OMIM) A subset of patients develop bilateral weakness 1 / 7739
31
 (OMIM) MRI may show cervical spinal cord atrophy 1 / 7739
32
 (OMIM) Dorsal and flexor muscles of the forearm are involved 1 / 7739
33
 (HPO:0003587) Insidious onset 11 / 7739
34
 (OMIM) EMG shows neurogenic changes consistent with denervation 1 / 7739
35
 (OMIM) Sparing of the brachioradialis muscle (gives appearance of 'oblique amyotrophy') 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Monomelic amyotrophy, also known as Hirayama disease, is characterized by insidious onset of weakness and wasting of the muscles of the hand and forearm. It is usually unilateral, but can be bilateral. It occurs most commonly as a ...
Clinical Description OMIM Hirayama et al. (1959) first described juvenile muscular atrophy of an upper extremity in Japanese patients. Hirayama (1972) reported 38 patients with juvenile nonprogressive muscular atrophy confined to the hand and forearm.

Gucuyener et al. (1991) ...
Molecular genetics OMIM By whole-exome sequencing of 4 unrelated Korean boys with monomelic amyotrophy, followed by selective genotyping of candidate variants in 24 patients, Lim et al. (2012) found a significant association between the disorder and 2 SNPs in 2 different ...