Alternative titles; symbols
SNOMEDCT: 771302009; ORPHA: 140468, 206580; DO: 0111213;
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
Gene/Locus |
Gene/Locus MIM number |
|---|---|---|---|---|---|---|
| 1p36.31 | Neuronopathy, distal hereditary motor, autosomal recessive 4 | 611067 | Autosomal recessive | 3 | PLEKHG5 | 611101 |
A number sign (#) is used with this entry because of evidence that autosomal recessive distal hereditary motor neuronopathy-4 (HMNR4) is caused by homozygous mutation in the gene encoding pleckstrin homology domain-containing protein, family G member 5 (PLEKHG5; 611101) on chromosome 1p36.
For a discussion of genetic heterogeneity of autosomal recessive HMN, see HMNR1 (604320).
Maystadt et al. (2006) reported a large consanguineous family from Mali in which 5 sibs, including a pair of monozygotic twins, had early onset of severe distal spinal muscular atrophy. Four of the sibs had onset of difficulty walking and climbing stairs between ages 2 and 3.5 years, leading to loss of ambulation and necessitating a wheelchair from ages 7.5 to 9 years. Two patients developed severely decreased respiratory function due to muscle weakness and required tracheotomy in their teens. Other features included pes equinovarus, finger muscle contractures, scapular and pelvic girdle muscle weakness and atrophy, scapular winging, hyperlordosis, and scoliosis. Neurophysiologic studies showed muscle denervation suggestive of anterior horn cell disease. Deep tendon reflexes were absent, and sensation was normal. Sural nerve biopsy in 1 patient was normal. All patients had normal mental development. The fifth sib showed a slightly milder disease course, with onset at 11.5 years and retention of ability to walk with difficulty at age 20 years. The phenotype was classic for a lower motor neuron disease; genetic analysis excluded linkage to the SMN1 (600354) and SOD1 (147450) genes.
The transmission pattern of HMNR4 in the family reported by Maystadt et al. (2007) was consistent with autosomal recessive inheritance.
By genomewide linkage analysis of a large Malian family with autosomal recessive distal spinal muscular atrophy (DSMA), Maystadt et al. (2006) identified a locus, referred to here as DSMA4, on chromosome 1p36. Homozygosity mapping defined a 3.9-cM interval between D1S508 and D1S2633 (maximum lod score of 3.79 at D1S253).
In the large inbred Malian family with HMNR4 reported by Maystadt et al. (2006), Maystadt et al. (2007) identified a homozygous missense mutation in the PLEKHG5 gene (611101.0001).
Maystadt, I., Rezsohazy, R., Barkats, M., Duque, S., Vannuffel, P., Remacle, S., Lambert, B., Najimi, M., Sokal, E., Munnich, A., Viollet, L., Verellen-Dumoulin, C. The nuclear factor kappa-beta-activator gene PLEKHG5 is mutated in a form of autosomal recessive lower motor neuron disease with childhood onset. Am. J. Hum. Genet. 81: 67-76, 2007. [PubMed: 17564964] [Full Text: https://doi.org/10.1086/518900]
Maystadt, I., Zarhrate, M., Leclair-Richard, D., Estournet, B., Barois, A., Renault, F., Routon, M.-C., Durand, M.-C., Lefebvre, S., Munnich, A., Verellen-Dumoulin, C., Viollet, L. A gene for an autosomal recessive lower motor neuron disease with childhood onset maps to 1p36. Neurology 67: 120-124, 2006. [PubMed: 16728649] [Full Text: https://doi.org/10.1212/01.wnl.0000223834.55225.2d]