Spinal Muscular atrophy Life expectancy

Spinal muscular atrophy life expectancy will mainly depend on the age when the symptoms start appearing in the person.

Life expectancy of someone with SMA ?

The earlier the Spinal Muscular atophy is observed in the child, lesser would be the predicted life span.
The bigger issue in making statements about Spinal muscular atrophy life expectancy is the variability of severity in different patients.
There are four types of SMA, all the four have different age of onset.
This obviously means patient with each type will have a different life expectancy.

Spinal muscular atrophy type 1 Life expectancy (SMA type 1)

In general, Life span of SMA type 1 would be mostly the least of all the four SMA types.
SMA type 1 also called as is supposed to be the most sever life threatening disease of all four SMA types.
SMA type 1 is observed at a very early age of say even 6 to 8 months or even during birth.
Hence SMA type 1 is also called as Infantile Spinal Muscular atrophy.

SMA type 1 mostly limits a person life. The affected children may die early if the severity observed is very high. Doctors sometimes indicate the symptoms like from 1.1 to 1.9. Its better for the family to get this clarified from the Doctor or medical team before making any judgments about the Life expectancy.

Longest living with SMA type 1

All the same, it is heartening to know that there have been cases of children living longer more than 10 years with SMA type 1.
Read here  about Lizza who as per the Doctors was not supposed to live longer than 2 years.

SMA type 1 Life expectancy

Lizza living bravely with SMA type 1 Life expectancy


This could possibly be a case of one of the longest living SMA type 1.




Even Brianna McDanel, who died in Jan 2015 was fifteen years old.

Brianna McDanel who was first diagnosed with SMA type 1, later changed to SMA type1/2

Brianna McDanel who was first diagnosed with SMA type 1, later changed to SMA type1/2


She was diagnosed with SMA type 1 and later retyped to SMA type1/2.It is important to remember that she had very good support from the care team and family.
Excellent medical assist support could make a measurable difference in Life expectancy for SMA type 1

The most important point considering Spinal Muscular atrophy type 1 life expectancy is the type of treatment and medical assistance the patient is provided.

Survival and Life expectancy research study for SMA type 1

To explain it better, here is a study of Life expectancy and survival rate made for some patients of Spinal muscular atrophy type 1.

Number of SMA type 1 patients enrolled:194(91 females and 103 males).

Nature of medical assistance and number of patients:

  • NT – Nature take its course (121 patients i.e 62.3%)
  • TV  – Tracheostomy and invasive mechanical ventilation(42, i.e 21.7%)
  • NRA – Continuous noninvasive respiratory muscle aid (16%, i.e 31 patients)

NRA includes assistance in cough and ventilation of non invasive type.

Study findings

In general patients with invasive type of assistance (TV) fared better  than non invasive type assistance or NT type patients.

Life expectancy of  24 months: 95% for TV and 67% for NRA patients.

Life expectancy of 48 months:89.43% for TV and 45% for NRA patients.

Inspite of this it was observed that statistically the patients opting for TV the best life prolonging treatment reduced from 50% to 12.7& from the period 1992 to 1998 to 2005-2010. This could have been obviously because TV is invasive assistance causing discomfort. And quite in line with that there was an approximate increase from 8.1% to 22.7 percent in that same period for NT. NT being non invasive and TV being invasive type of assistance. Quite notably patients wanting to live without any of this assistance also increased from 8.1% to 22.7 percent in that same period.

All in all the above results showed how the families of the patients gave higher importance to quality of life than prolonging life expectancy of SMA type 1 patients.

Spinal muscular atrophy type 2 Life expectancy (SMA type 2)

SMA type 2 is less severe than SMA type 1. SMA type 2 signs or indications are seen generally after 18 months. Spinal muscular atrophy life expectancy of SMA type 2 is generally different from patient to patient Some patients with SMA could have a very short span and some could live till adulthood.
Life expectancy could be improved by providing proper care and support to the patient. They could live a much better life with proper care and support standards.
The weakness of respiratory muscle is an important point to be noted and monitored for SMA type 2. This makes them prone to respiratory issues.

Spinal muscular atrophy type 3 Life expectancy (SMA type 3)

SMA type 3 also called as Kugelberg Welander disease is milder than SMA type 2 and SMA type 1. Age of onset is also much later than SMA type 2 could be say after 1.5 to 2 years. The patients would be able to stand and walk.
The Life expectancy could be till adult, they might even have a normal life with proper support.
The important point would be swallowing issues later in life.

Spinal muscular atrophy type 4 Life expectancy (SMA type 4)

SMA type 4 is comparatively seen less amongst all of the SMA types. The SMA type 4 symptoms are observed in adult age. SMA type 4 is much milder than SMA type 1, SMA type 2 and SMA type 3. The patient can easily move and symptoms start showing around the age of 25 and 45.
The Life span of SMA type 4 is better than all.

Read more about What is muscle atrophy ?

Posted in Spinal Muscular atrophy.

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