GC: n
S: NORD (last access: 15 December 2025); MDA (last access: 15 December 2025); NCBI (last access: 15 December 2025).
N: 1. – spinal (adj): «of or pertaining to the backbone,» 1570s, from Late Latin spinalis «of or pertaining to a thorn or the spine,» from Latin spina «backbone; thorn».
– muscular (adj): 1680s, «pertaining to muscles,» from Latin musculus muscle (n.) + -ar. Earlier in same sense was musculous (early 15c., from Latin musculosus).
– atrophy (n): «a wasting away through lack of nourishment,» 1610s (atrophied is from 1590s), from French atrophie, from Late Latin atrophia, from Greek atrophia «a wasting away,» abstract noun from atrophos «ill-fed, un-nourished,» from a– «not, without» + trophē «nourishment,» from trephein «to fatten».
2. Spinal muscular atrophy (SMA) is a genetic disease affecting the central nervous system, peripheral nervous system, and voluntary muscle movement (skeletal muscle).
- Most of the nerve cells that control muscles are located in the spinal cord, which accounts for the word spinal in the name of the disease. SMA is muscular because its primary effect is on muscles, which don’t receive signals from these nerve cells. Atrophy is the medical term for getting smaller, which is what generally happens to muscles when they’re not stimulated by nerve cells.
SMA involves the loss of nerve cells called motor neurons in the spinal cord and is classified as a motor neuron disease.
3. Chromosome 5-related SMA is caused by a deficiency of a motor neuron protein called SMN, for “survival of motor neuron.” This protein, as its name implies, seems to be necessary for normal motor neuron function. SMN plays a pivotal role in gene expression in motor neurons. Its deficiency is caused by genetic flaws (mutations) on chromosome 5 in a gene called SMN1. The most common mutation in the SMN1 gene within patients diagnosed with SMA is a deletion of a whole segment, called exon 7. Neighboring SMN2 genes can in part compensate for nonfunctional SMN1 genes as there is 99% identity between these two genes.
- Other rare forms of SMA (non-chromosome 5) are caused by mutations in genes other than SMN1.
4. Spinal muscular atrophy (SMA) is often grouped into types. These are based on the age that symptoms begin and how they affect sitting, standing and walking.
The 4 most common types of SMA are:
- Type 1: appears before 6 months of age.
- Type 2: develops between 6 and 17 months.
- Type 3: onset occurs between 18 months and 17 years.
- Type 4: begins in adulthood, at 18 years old or older.
5. Cultural Interrelation: We can mention the film 39 Pounds of Love (2005), directed by Dani Menkin and starring Ami Ankilewitz. It is a documentary that tells the story of Ami Ankilewitz, an Israeli man born in the United States who suffers from a rare form of muscular dystrophy that leaves him immobile except for one finger, which he uses to work as a 3D animator. Despite doctors claiming he would not live past the age of six, Ami sets out, more than three decades later, on a journey across the United States to find the doctor who predicted his death, in a moving reflection on perseverance, hope, and love for life.
S: 1. Etymonline – https://www.etymonline.com/word/spinal, https://www.etymonline.com/word/muscular, https://www.etymonline.com/word/atrophy (last access: 15 December 2025). 2 & 3. MDA (last access: 15 December 2025). 4. NHS (last access: 15 December 2025). 5. IMDb (last access: 15 December 2025).
SYN: SMA, SMN-related SMA, classic SMA, chromosome 5 SMA.
S: NORD (last access: 15 December 2025).