Table 5

Some examples of genotype/phenotype correlations in MND associated with specific SOD1 gene mutations

MutationInheritancePenetrance in affected familiesDistribution, phenotypeSurvival from onset of symptoms
Alanine to valine, exon 1, codon 4 (A4V) Aspartate to alanine, exon 4, codon 90 (D90A)Autosomal dominantCompleteNorth America. Rapidly progressive mainly LMN syndrome, limb or bulbar onset<2 years
Autosomal recessive (homozygous): “Scandinavian recessive D90A MND/ALS”CompleteScandinavia; Russia, France, Germany, North America. Slowly progressive, presenting as spastic paraparesis, evolving into limb and bulbar MND. Bladder and sensory symptoms common10–20 years
Aspartate to alanine, exon 4, codon 90 (D90A)Autosomal dominant (heterozygous)VariableBelgium, UK, USA, Russia. Variable phenotypeVariable; short or long survival
Glutamate to lysine, exon 4, codon 100 (E100K)Autosomal dominantVariableAfro-American, German families; variable phenotype>10 years
Isoleucine to threonine, exon 4, codon 113 (I113T)Autosomal dominantVery variable; apparently sporadic cases with I113T mutation not uncommonNorth America, Scotland. Variable phenotypeVariable; short or long (>10 years)