Sarcoglycan genes

Genes associated with Limb girdle muscular dystrophy types 2C, 2D, 2E and 2F. Mutations in these genes result in the reduction or absence of the sarcoglycan proteins (g, a, b and d).

Sarcoglycan proteins

There are four sarcoglycan proteins - g-sarcoglycan, a-sarcoglycan, b-sarcoglycan and d-sarcoglycan - which link the inside and outside of the cell across the membrane. They bind to other components in the dystrophin-glycoprotein complex.

Sarcoglycanopathies

Limb girdle muscular dystrophies which involve the sarcoglycan genes.

Sarcolemma

A membrane or skin surrounding each muscle fibre.

Satellite cells

Cells which repair damaged muscle fibres. Usually dormant, the cells become activated and rapidly increase, when the muscle fibre is damaged or needs to grow. They produce large numbers of myoblasts that fuse together with surviving parts of the damaged muscle fibre to fill any gaps. Satellite cells are a special type of stem cell.


Scoliosis

Curvature of the spine.

Self cells

Cells from your own body.

Sex chromosomes

The X and Y chromosomes determine the sex of an individual. Females have two X chromosomes; males have an X and Y chromosome.


SMN gene (Survival Motor Neuron gene)

Occurs in two forms SMN1 and SMN2. Spinal muscular atrophy is associated with the loss of the SMN1 genes.


SMN protein (Survival Motor Neuron protein)

Produced by the SMN genes and reduced in individuals with spinal muscular atrophy.

Spinal Muscular Atrophy

Genetic conditions resulting in progressive muscle wasting and loss of lower motor neurons in the spinal cord. Spinal Muscular Atrophy is caused by the absence of SMN1 genes and follows an autosomal recessive pattern of inheritance.


Splicing

The removal of introns from a section of genetic code to leave only the useful exons.


Stem cells

Cells that have not yet specialised to form a particular cell type, and can still become muscle cells or other types of cell.


Stop codon

A section of DNA code that terminates protein production.