Spinal Muscular Atrophy (SMA) is a genetic disease that causes progressive muscle degeneration. There are several types of SMA which are defined by the severity and the age of the child at onset. Our daughter Falynn was born with Type 1 SMA, which is the most severe form. The life expectancy of infants with Type 1 is only 2 years. The muscle weakness will eventually eliminate the ability for a child to sit, walk, eat, hold their heads up and even breathe.
• 25% chance the Child will get unaffected genes from the mother and the father. (Unaffected Son)
• 25% chance the Child will get affected gene from the mother. (Carrier Daughter)
• 25% chance the Child will get affected gene from the father. (Carrier Son)
• 25% Chance the Child will get affected gene from the mother and the father. (Daughter with SMA)
• Type I - Babies diagnosed with SMA type I, cannot sit-up and do not generally live past two years of age. It's the most severe form of SMA with a quick and unexpected onset. Progressive motor neuron death causes a rapid break down of the major bodily organs especially of the respiratory system. Also known as Werdnig-Hoffmann disease.
• Type II - Children who are never able to stand and walk but who are able to maintain a sitting position at least some time in their life. Also known as Dubowitz disease.
• Type III - The juvenile form usually manifests after 18 months of age and describes patients who are able to walk without support at some time, although many later lose this ability. Also known as Kugelberg-Welander disease.
• Type IV - The adult-onset form where a person can walk at some point but weakening of the muscles can cause the patient to be wheelchair-bound.
• Type 0 - Sub-category of Type I. Infants born with type 0 usually have no movement of any muscles from birth and are considered the most severe form of SMA type 1. These children have an average lifespan of 6-months.
• SMARD - Spinal Muscular Atrophy with Respiratory Distress. SMARD is caused by mutations on the IGHMBP2 gene, whereas 'regular' SMA is caused by mutations of the SMN gene. SMARD typically attacks breathing musculature first, and moves to other muscles. Every living child with SMARD is trached and ventilated. SMARD is the rarest type in the SMA family.
