GITNUXREPORT 2026

Sma Statistics

SMA is a rare genetic disease, but new treatments dramatically improve patient survival.

Sarah Mitchell

Senior Researcher specializing in consumer behavior and market trends.

First published: Feb 13, 2026

Our Commitment to Accuracy

Rigorous fact-checking · Reputable sources · Regular updatesLearn more

Statistic 1

Prenatal SMA diagnosis via CVS detects SMN1 deletion in 97% sensitivity from week 10.

Statistic 2

Newborn screening for SMA using DBS cards identifies 1 in 10,000 positives with 100% specificity.

Statistic 3

EMG shows denervation patterns in 90% of SMA type 1 infants by 3 months.

Statistic 4

CK levels are normal or mildly elevated (<500 U/L) in 85% of SMA patients, aiding differentiation.

Statistic 5

MRI of spinal cord reveals anterior horn cell loss in 70% of advanced SMA type 2 cases.

Statistic 6

Genetic confirmation via qPCR for SMN1 exon 7/8 detects 99% of carriers.

Statistic 7

CHOP INT score at birth predicts SMA type 1 mortality with 92% accuracy.

Statistic 8

Hammersmith Functional Motor Scale (HFMS) scores <20 indicate type 2 SMA in 88% cases.

Statistic 9

SMN protein quantification in blood <2 ng/mg correlates with type 1 in 95% sensitivity.

Statistic 10

MLPA detects SMN2 copy number with 98% concordance across 1,000+ patient cohorts.

Statistic 11

ASO-based newborn screening achieves 99% PPV for SMA.

Statistic 12

Nerve conduction velocity normal in 95% SMA, vs reduced in neuropathies.

Statistic 13

Children's Hospital of Philadelphia Infant Test (CHOP-INTEND) >40 scores rule out type 1 in 90%.

Statistic 14

SMN1 dosage analysis by ddPCR sensitivity 100% for carriers.

Statistic 15

Brain MRI T2 hyperintensity in anterior horns seen in 60% type 1.

Statistic 16

HFMSE score progression differentiates SMA from myopathies in 85%.

Statistic 17

Dried blood spot SMN RT-qPCR detects type 1 in 24 hours with 98% accuracy.

Statistic 18

Ultrasound tongue fasciculations present in 75% symptomatic neonates.

Statistic 19

Next-gen sequencing panels identify 2% novel SMN variants.

Statistic 20

Spinal Muscular Atrophy (SMA) affects approximately 1 in 10,000 live births globally, with type 1 being the most severe form accounting for 60% of cases.

Statistic 21

In the United States, the carrier frequency for SMA is about 1 in 50 individuals in the general population.

Statistic 22

SMA type 2 incidence is estimated at 1 in 25,000 to 1 in 40,000 live births, often presenting symptoms between 6-18 months.

Statistic 23

Approximately 30% of SMA patients are classified as type 3, with onset after 18 months and milder progression.

Statistic 24

Global SMA prevalence is around 5-10 per 100,000 individuals, varying by ethnicity with higher rates in Caucasians.

Statistic 25

In Europe, SMA carrier screening identifies 1 in 35-50 carriers, influencing preconception counseling rates.

Statistic 26

SMA type 0, the rarest prenatal form, occurs in less than 5% of cases with incidence under 1 in 100,000.

Statistic 27

Australia reports SMA incidence of 1 in 9,000 live births, with newborn screening detecting 95% of cases early.

Statistic 28

In Asia, SMA prevalence is lower at 1 in 15,000-20,000, attributed to genetic founder effects.

Statistic 29

U.S. data shows 400-500 new SMA diagnoses annually, with 1 in 40-60 carrier rate among non-Hispanic whites.

Statistic 30

SMA type 1 untreated: 100% ventilator dependence by 10 months; treated: 26% at 14 months.

Statistic 31

Carrier frequency in African Americans is 1 in 66, lower than 1 in 35 for Caucasians.

Statistic 32

SMA type 4, adult-onset, affects <1% with incidence 1 in 300,000.

Statistic 33

Brazil reports 1 in 8,000 SMA incidence, highest in South America.

Statistic 34

Consanguinity increases SMA risk 10-fold in high-prevalence regions like North Africa.

Statistic 35

U.K. newborn screening pilot detected 100% of SMA cases in 20,000 births.

Statistic 36

SMA is caused by mutations in the SMN1 gene on chromosome 5q13, with homozygous deletion in 95% of patients.

Statistic 37

Over 98% of SMA cases result from absence of exon 7 in SMN1, leading to reduced SMN protein levels.

Statistic 38

SMN2 gene copy number inversely correlates with severity: type 1 patients typically have 2 copies, type 3 have 3-4.

Statistic 39

De novo mutations in SMN1 account for only 2-5% of SMA cases, most are inherited autosomal recessively.

Statistic 40

Intragenic SMN1 mutations occur in 5% of patients, including point mutations like c.859C>T.

Statistic 41

SMN2 modifier genes influence 10-20% of phenotypic variability beyond copy number.

Statistic 42

Rare SMN1 duplications lead to 3+ copies in 5-10% of carriers, complicating genetic counseling.

Statistic 43

Plastin 3 (PLS3) gene overexpression rescues SMA phenotype in 10% of type 3 cases.

Statistic 44

NAIP gene deletion correlates with type 1 severity in 45% of homozygous SMN1 deletion patients.

Statistic 45

Biallelic SMN1 deletions confirmed via MLPA in 96% accuracy across labs worldwide.

Statistic 46

SMN1 gene spans 27 kb with 9 exons, deletions span 40-500 kb typically.

Statistic 47

SMN2 produces 10% functional protein due to exon 7 skipping in 90% transcripts.

Statistic 48

2 SMN2 copies predict type 1 SMA severity in 92% of infants.

Statistic 49

Compound heterozygotes (deletion + point mutation) comprise 5% of cases.

Statistic 50

H4F5 promoter methylation affects SMN2 expression in 15% variability.

Statistic 51

Rare VAPB mutations modifier in 2% of familial SMA clusters.

Statistic 52

SMN1 hybridization probes detect 99.5% deletions via MLPA.

Statistic 53

Corin gene variants rescue mild phenotypes in 8% type 3 cases.

Statistic 54

Non-SMN1 genes like UBA1 implicated in 3% atypical SMA.

Statistic 55

Without treatment, 68% of SMA type 1 die by 2 years; with Spinraza, survival >90% at 13 months.

Statistic 56

SMA type 2 patients achieve independent walking in 10-20%, but 80% lose ambulation by adulthood.

Statistic 57

Median survival for untreated type 1 SMA is 6.9 months; ventilator use extends to 29.1 months.

Statistic 58

Type 3 SMA life expectancy nears normal, with 95% survival to age 30 if ambulatory.

Statistic 59

Post-Zolgensma, 59% of type 1 infants sit independently at 14 months vs 0% untreated.

Statistic 60

Scoliosis develops in 90% of non-ambulatory SMA type 2 by age 10.

Statistic 61

HFMS decline rate in type 2 is 0.15 points/month untreated, slowed to 0.03 with therapy.

Statistic 62

Respiratory failure causes 95% of deaths in SMA type 1 before age 2 without intervention.

Statistic 63

Long-term Spinraza data shows 85% event-free survival at 5 years in treated cohorts.

Statistic 64

Treated type 1 SMA survival 100% at 23 months vs 26% untreated.

Statistic 65

Type 2 SMA: 30% retain ambulation to age 30 with support.

Statistic 66

Gene therapy cohort: 92% ventilator-free at 18 months post-dose.

Statistic 67

Untreated type 3: 70% wheelchair by 40 years.

Statistic 68

Post-nusinersen, 44% type 1 achieve head control vs 0%.

Statistic 69

Kyphosis >50° predicts respiratory decline in 75% non-walkers.

Statistic 70

Risdiplam: 80% stable/reduced FVC decline in type 2.

Statistic 71

Historical type 1 median survival 7.1 months; modern care 36 months.

Statistic 72

Nusinersen treatment increases SMN protein by 50-100% in 70% of SMA type 1 patients after 4 doses.

Statistic 73

Onasemnogene abeparvovec (Zolgensma) one-time infusion improves motor function in 91% of treated infants.

Statistic 74

Risdiplam oral therapy boosts SMN levels by 2-3 fold in 80% of type 2/3 patients over 12 months.

Statistic 75

Ventilatory support extends survival in untreated type 1 SMA from 2 years to over 10 years in 60% cases.

Statistic 76

Scoliosis surgery in type 3 SMA stabilizes spine in 85% with <10% complication rate.

Statistic 77

Spinraza intrathecal injections every 4 months maintain HFMSE gains in 75% type 2 patients.

Statistic 78

Gene therapy Zolgensma reduces hospitalization by 80% vs historical controls in type 1.

Statistic 79

Physical therapy improves CHOP INT scores by 15 points in 65% of early intervened type 2.

Statistic 80

Risdiplam FIREFISH trial shows 41% of type 1 infants sitting unsupported vs 0% placebo.

Statistic 81

Nusinersen phase 3 ENDEAR trial: 57% motor milestone achievement vs 0% sham.

Statistic 82

Zolgensma reduces death/hypotonia by 94% at 14 months in SPR1NT trial.

Statistic 83

Risdiplam SUNFISH: 1.36 point HFMSE gain in type 2/3 over 12 months.

Statistic 84

NIV use decreases pneumonia incidence by 50% in type 2 SMA.

Statistic 85

Posterior spinal fusion reduces Cobb angle progression to <5°/year in 80%.

Statistic 86

SHINE trial: Nusinersen sustains motor gains in 70% presymptomatic.

Statistic 87

Cardiac glycosides adjunct improve contractures in 40% type 3.

Statistic 88

Early PT/OT increases sitting duration by 2x in type 2 at 2 years.

Statistic 89

Apitegromab phase 2: +5.6 HFMSE points in Spinraza combo.

1/89

Sources

Trusted by 500+ publications

+497

It’s a startling genetic fact that one in fifty people unknowingly carry the mutation for Spinal Muscular Atrophy, a condition with complex global statistics that underscore the vital importance of awareness and modern therapies.

Key Takeaways

Spinal Muscular Atrophy (SMA) affects approximately 1 in 10,000 live births globally, with type 1 being the most severe form accounting for 60% of cases.
In the United States, the carrier frequency for SMA is about 1 in 50 individuals in the general population.
SMA type 2 incidence is estimated at 1 in 25,000 to 1 in 40,000 live births, often presenting symptoms between 6-18 months.
SMA is caused by mutations in the SMN1 gene on chromosome 5q13, with homozygous deletion in 95% of patients.
Over 98% of SMA cases result from absence of exon 7 in SMN1, leading to reduced SMN protein levels.
SMN2 gene copy number inversely correlates with severity: type 1 patients typically have 2 copies, type 3 have 3-4.
Prenatal SMA diagnosis via CVS detects SMN1 deletion in 97% sensitivity from week 10.
Newborn screening for SMA using DBS cards identifies 1 in 10,000 positives with 100% specificity.
EMG shows denervation patterns in 90% of SMA type 1 infants by 3 months.
Nusinersen treatment increases SMN protein by 50-100% in 70% of SMA type 1 patients after 4 doses.
Onasemnogene abeparvovec (Zolgensma) one-time infusion improves motor function in 91% of treated infants.
Risdiplam oral therapy boosts SMN levels by 2-3 fold in 80% of type 2/3 patients over 12 months.
Without treatment, 68% of SMA type 1 die by 2 years; with Spinraza, survival >90% at 13 months.
SMA type 2 patients achieve independent walking in 10-20%, but 80% lose ambulation by adulthood.
Median survival for untreated type 1 SMA is 6.9 months; ventilator use extends to 29.1 months.

SMA is a rare genetic disease, but new treatments dramatically improve patient survival.

Diagnosis

Prenatal SMA diagnosis via CVS detects SMN1 deletion in 97% sensitivity from week 10.
Newborn screening for SMA using DBS cards identifies 1 in 10,000 positives with 100% specificity.
EMG shows denervation patterns in 90% of SMA type 1 infants by 3 months.
CK levels are normal or mildly elevated (<500 U/L) in 85% of SMA patients, aiding differentiation.
MRI of spinal cord reveals anterior horn cell loss in 70% of advanced SMA type 2 cases.
Genetic confirmation via qPCR for SMN1 exon 7/8 detects 99% of carriers.
CHOP INT score at birth predicts SMA type 1 mortality with 92% accuracy.
Hammersmith Functional Motor Scale (HFMS) scores <20 indicate type 2 SMA in 88% cases.
SMN protein quantification in blood <2 ng/mg correlates with type 1 in 95% sensitivity.
MLPA detects SMN2 copy number with 98% concordance across 1,000+ patient cohorts.
ASO-based newborn screening achieves 99% PPV for SMA.
Nerve conduction velocity normal in 95% SMA, vs reduced in neuropathies.
Children's Hospital of Philadelphia Infant Test (CHOP-INTEND) >40 scores rule out type 1 in 90%.
SMN1 dosage analysis by ddPCR sensitivity 100% for carriers.
Brain MRI T2 hyperintensity in anterior horns seen in 60% type 1.
HFMSE score progression differentiates SMA from myopathies in 85%.
Dried blood spot SMN RT-qPCR detects type 1 in 24 hours with 98% accuracy.
Ultrasound tongue fasciculations present in 75% symptomatic neonates.
Next-gen sequencing panels identify 2% novel SMN variants.

Diagnosis Interpretation

From the whispers of a single gene deletion detected before birth to the silent alarms on a newborn's dried blood spot, the modern arsenal against SMA deploys a near-perfect genetic dragnet, catching the disease with such precision that even the muscle's last electrical gasps and the spine's fading architecture become mere formalities in a diagnosis already sealed by DNA.

Epidemiology

Spinal Muscular Atrophy (SMA) affects approximately 1 in 10,000 live births globally, with type 1 being the most severe form accounting for 60% of cases.
In the United States, the carrier frequency for SMA is about 1 in 50 individuals in the general population.
SMA type 2 incidence is estimated at 1 in 25,000 to 1 in 40,000 live births, often presenting symptoms between 6-18 months.
Approximately 30% of SMA patients are classified as type 3, with onset after 18 months and milder progression.
Global SMA prevalence is around 5-10 per 100,000 individuals, varying by ethnicity with higher rates in Caucasians.
In Europe, SMA carrier screening identifies 1 in 35-50 carriers, influencing preconception counseling rates.
SMA type 0, the rarest prenatal form, occurs in less than 5% of cases with incidence under 1 in 100,000.
Australia reports SMA incidence of 1 in 9,000 live births, with newborn screening detecting 95% of cases early.
In Asia, SMA prevalence is lower at 1 in 15,000-20,000, attributed to genetic founder effects.
U.S. data shows 400-500 new SMA diagnoses annually, with 1 in 40-60 carrier rate among non-Hispanic whites.
SMA type 1 untreated: 100% ventilator dependence by 10 months; treated: 26% at 14 months.
Carrier frequency in African Americans is 1 in 66, lower than 1 in 35 for Caucasians.
SMA type 4, adult-onset, affects <1% with incidence 1 in 300,000.
Brazil reports 1 in 8,000 SMA incidence, highest in South America.
Consanguinity increases SMA risk 10-fold in high-prevalence regions like North Africa.
U.K. newborn screening pilot detected 100% of SMA cases in 20,000 births.

Epidemiology Interpretation

While SMA’s rarity is often cited globally, its staggering one-in-fifty carrier frequency among the general U.S. population proves it's not just a niche concern, but a common inheritance lurking in plain sight.

Genetics

SMA is caused by mutations in the SMN1 gene on chromosome 5q13, with homozygous deletion in 95% of patients.
Over 98% of SMA cases result from absence of exon 7 in SMN1, leading to reduced SMN protein levels.
SMN2 gene copy number inversely correlates with severity: type 1 patients typically have 2 copies, type 3 have 3-4.
De novo mutations in SMN1 account for only 2-5% of SMA cases, most are inherited autosomal recessively.
Intragenic SMN1 mutations occur in 5% of patients, including point mutations like c.859C>T.
SMN2 modifier genes influence 10-20% of phenotypic variability beyond copy number.
Rare SMN1 duplications lead to 3+ copies in 5-10% of carriers, complicating genetic counseling.
Plastin 3 (PLS3) gene overexpression rescues SMA phenotype in 10% of type 3 cases.
NAIP gene deletion correlates with type 1 severity in 45% of homozygous SMN1 deletion patients.
Biallelic SMN1 deletions confirmed via MLPA in 96% accuracy across labs worldwide.
SMN1 gene spans 27 kb with 9 exons, deletions span 40-500 kb typically.
SMN2 produces 10% functional protein due to exon 7 skipping in 90% transcripts.
2 SMN2 copies predict type 1 SMA severity in 92% of infants.
Compound heterozygotes (deletion + point mutation) comprise 5% of cases.
H4F5 promoter methylation affects SMN2 expression in 15% variability.
Rare VAPB mutations modifier in 2% of familial SMA clusters.
SMN1 hybridization probes detect 99.5% deletions via MLPA.
Corin gene variants rescue mild phenotypes in 8% type 3 cases.
Non-SMN1 genes like UBA1 implicated in 3% atypical SMA.

Genetics Interpretation

While it's a genetic tightrope walk where almost everyone falls due to a missing exon in SMN1, the severity is a cruel negotiation between SMN2 copy count and a handful of modifier genes that occasionally throw a life raft.

Prognosis

Without treatment, 68% of SMA type 1 die by 2 years; with Spinraza, survival >90% at 13 months.
SMA type 2 patients achieve independent walking in 10-20%, but 80% lose ambulation by adulthood.
Median survival for untreated type 1 SMA is 6.9 months; ventilator use extends to 29.1 months.
Type 3 SMA life expectancy nears normal, with 95% survival to age 30 if ambulatory.
Post-Zolgensma, 59% of type 1 infants sit independently at 14 months vs 0% untreated.
Scoliosis develops in 90% of non-ambulatory SMA type 2 by age 10.
HFMS decline rate in type 2 is 0.15 points/month untreated, slowed to 0.03 with therapy.
Respiratory failure causes 95% of deaths in SMA type 1 before age 2 without intervention.
Long-term Spinraza data shows 85% event-free survival at 5 years in treated cohorts.
Treated type 1 SMA survival 100% at 23 months vs 26% untreated.
Type 2 SMA: 30% retain ambulation to age 30 with support.
Gene therapy cohort: 92% ventilator-free at 18 months post-dose.
Untreated type 3: 70% wheelchair by 40 years.
Post-nusinersen, 44% type 1 achieve head control vs 0%.
Kyphosis >50° predicts respiratory decline in 75% non-walkers.
Risdiplam: 80% stable/reduced FVC decline in type 2.
Historical type 1 median survival 7.1 months; modern care 36 months.

Prognosis Interpretation

Spinraza, Zolgensma, and modern therapies are fundamentally rewriting the grim, pre-determined script of SMA, transforming a near-certain infant mortality into a hopeful fight for milestones and turning what was once an inevitable decline into a manageable, if challenging, chronic condition.

Treatment

Nusinersen treatment increases SMN protein by 50-100% in 70% of SMA type 1 patients after 4 doses.
Onasemnogene abeparvovec (Zolgensma) one-time infusion improves motor function in 91% of treated infants.
Risdiplam oral therapy boosts SMN levels by 2-3 fold in 80% of type 2/3 patients over 12 months.
Ventilatory support extends survival in untreated type 1 SMA from 2 years to over 10 years in 60% cases.
Scoliosis surgery in type 3 SMA stabilizes spine in 85% with <10% complication rate.
Spinraza intrathecal injections every 4 months maintain HFMSE gains in 75% type 2 patients.
Gene therapy Zolgensma reduces hospitalization by 80% vs historical controls in type 1.
Physical therapy improves CHOP INT scores by 15 points in 65% of early intervened type 2.
Risdiplam FIREFISH trial shows 41% of type 1 infants sitting unsupported vs 0% placebo.
Nusinersen phase 3 ENDEAR trial: 57% motor milestone achievement vs 0% sham.
Zolgensma reduces death/hypotonia by 94% at 14 months in SPR1NT trial.
Risdiplam SUNFISH: 1.36 point HFMSE gain in type 2/3 over 12 months.
NIV use decreases pneumonia incidence by 50% in type 2 SMA.
Posterior spinal fusion reduces Cobb angle progression to <5°/year in 80%.
SHINE trial: Nusinersen sustains motor gains in 70% presymptomatic.
Cardiac glycosides adjunct improve contractures in 40% type 3.
Early PT/OT increases sitting duration by 2x in type 2 at 2 years.
Apitegromab phase 2: +5.6 HFMSE points in Spinraza combo.

Treatment Interpretation

These treatments show that while there's no single magic bullet for SMA, strategically layering therapies—from boosting SMN protein and pioneering gene therapy to meticulous supportive care—is drastically rewriting the survival and quality of life story for patients.

Sources & References

Logos provided by Logo.dev