Proximal spinal muscular atrophy type 1

General Information (adopted from Orphanet):

Synonyms, Signs: SMA, INFANTILE ACUTE FORM
MUSCULAR ATROPHY, INFANTILE
SMA I
SMA-I
SMA1
Infantile spinal muscular atrophy
werdnig-hoffmann disease
Number of Symptoms 14
OrphanetNr: 83330
OMIM Id: 253300
ICD-10: G12.0
UMLs:
MeSH:
MedDRA:
Snomed:

Prevalence, inheritance and age of onset:

Prevalence: 1.25 of 100 000 [Orphanet]
Inheritance: Autosomal recessive
[Orphanet]
Age of onset: Neonatal
Infancy
[Orphanet]

Disease classification (adopted from Orphanet):

Parent Diseases: Proximal spinal muscular atrophy
 -Rare genetic disease
 -Rare neurologic disease

Symptom Information: Sort by abundance 

1
(HPO:0001308) Tongue fasciculations 18 / 7739
2
(HPO:0001284) Areflexia 198 / 7739
3
(HPO:0001558) Decreased fetal movement 74 / 7739
4
(HPO:0001629) Ventricular septal defect 316 / 7739
5
(HPO:0001631) Atria septal defect 274 / 7739
6
(HPO:0002093) Respiratory insufficiency 410 / 7739
7
(HPO:0003202) Skeletal muscle atrophy 281 / 7739
8
(OMIM) Normal motor conduction studies (initially) 1 / 7739
9
(OMIM) Affected children are unable to sit without support 1 / 7739
10
(OMIM) Muscle weakness, proximal, symmetric (lower limbs more affected than upper limbs) due to motor neuronopathy 5 / 7739
11
(OMIM) Facial muscle sparing 1 / 7739
12
(OMIM) Loss of lower alpha-motor neurons in the anterior horn of the spinal cord and lower brainstem 1 / 7739
13
(OMIM) EMG shows neurogenic abnormalities 8 / 7739
14
(OMIM) Congenital cardiac malformations have been rarely reported in severe cases 1 / 7739

Associated genes:

ClinVar (via SNiPA)

Gene symbol Variation Clinical significance Reference

Additional Information:

Description: (OMIM) Spinal muscular atrophy refers to a group of autosomal recessive neuromuscular disorders characterized by degeneration of the anterior horn cells of the spinal cord, leading to symmetrical muscle weakness and atrophy. SMA is the second most common lethal, ...
Diagnosis OMIM See 600354 for details on the molecular diagnosis of SMA.

- Prenatal Diagnosis

Daniels et al. (1992) and Melki et al. (1992) demonstrated the feasibility of prenatal diagnosis of SMA by the linkage principle. ...

Clinical Description OMIM Many groups observed the occurrence of different SMA subtypes within the same family, suggesting different manifestations of a single disease entity. Ghetti et al. (1971) reported that in many families 'malignant' Werdnig-Hoffmann disease coexisted with the Werdnig-Hoffmann disease ...
Genotype-Phenotype Correlations OMIM For a detailed discussion of genotype/phenotype correlations in spinal muscular atrophy, see 600354.

Burlet et al. (1996) found large-scale deletions involving both the SMN gene and its upstream (C212-C272) and downstream (NAIP) flanking markers in 43% ...

Molecular genetics OMIM Biros and Forrest (1999), Wirth (2000), and Ogino and Wilson (2004) provided reviews of the complex molecular basis of SMA. SMN1 and SMN2 lie within the telomeric and centromeric halves, respectively, of a large inverted repeat on chromosome ...
Population genetics OMIM Czeizel and Hamula (1989) and Czeizel (1991) estimated the prevalence of Werdnig-Hoffmann disease in Hungary to be 1 per 10,000 live births. The occurrence in sibs was 32%, a figure considered consistent with autosomal recessive inheritance complicated by ...