When individuals suffer from a genetic disorder like spinal muscular atrophy (SMA), they cannot control their muscle movements. It develops due to insufficient survival motor neuron (SMN) protein production. Two genes—SMN1 and SMN2—control the synthesis of this protein. If there is an abnormality in the representation of these genes, then babies can develop SMA. Patients find it challenging to stand, walk, control head movements, and even swallow when suffering from this condition. Herein, we discuss the different types of spinal muscle atrophy.

Different Types of Spinal Muscular Atrophy
Scientists have outlined five different types of spinal muscle atrophy. Among them, Type 0 is extremely rare and fatal. Pregnancies either get terminated midway or result in stillbirth in this type of SMA. Let’s take a look at the other types of SMA.

• Type 1
  Type 1 SMA, or Werdnig-Hoffmann disease, is one of the most widespread forms of this neurological disorder. This medical condition usually manifests itself when the baby is three months old. They cannot hold their head firmly without support. Babies having SMA 1 also find it challenging to gulp milk or other semi-solid foods. They have floppy arms and legs, and cannot sit without support. Doctors advocate disease-modifying therapies to manage this condition. But many infants show respiratory infections due to complications of SMA 1.
• Type 2
  Doctors usually diagnose Type 2 SMA among 3- to 15-month-old babies. It is also known as intermediate SMA or Dubowitz disease. Muscle wastage affects legs more than arms in Type 2 SMA. Although infants can sit without support, they can barely stand or walk without any assistance.  Moreover, children show difficulty in breathing when they fall asleep. The life expectancy of such patients depends on their breathing conditions. In many cases, patients live up to adolescence or young adulthood.
• Type 3
  Type 3 SMA is also known as Kugelberg-Welander disease. Symptoms of this condition usually appear after 18 months. Patients show shortening of muscles and tendons and scoliosis. They cannot walk freely or climb stairs. Many children need a wheelchair for movement. They may also show complications in respiratory functions. Timely implementations of disease-modifying therapies can help Type 3 SMA patients to have a normal life expectancy.
• Type 4
  Type 4 SMA usually does not manifest itself until a patient reaches 20 or 30 years of age. It is also known as adult SMA, and in most cases, symptoms are mild weakness in arms and legs. Patients may find it challenging to walk briskly or have slight breathing difficulties. However, this ailment does not affect the life expectancy of patients. Many patients do not even know about their medical issues until symptoms persist for years.

Knowing about the different types of spinal muscle atrophy can help you detect symptoms early on. An early diagnosis can pave the way for effective treatment, wherever possible.