Popularly known as Werdnig-Hoffmann disease, type 1 SMA is considered to be one of the most common types of spinal muscle atrophy (SMA). This condition generally affects children who are yet to reach the age of 6 months. Sometimes, this disease can be diagnosed even before the birth of the child. Like any other disease, the type 1 SMA also comes with many symptoms.

Symptoms of type 1 SMA can include the following:

1. Hypotonia
Hypotonia, also known as the floppy baby syndrome, is a medical term for muscle weakness. This is probably one of the common symptoms of the type 1 SMA as almost every patient suffering from this disease experiences this problem.

Some of the signs of hypotonia in an infant generally include:

• Having no control of the neck muscles which makes their head flop constantly
• The children are also unable to place even a small portion of the weight on their shoulder or leg muscles
• A quiet voice or weaker cry in infants who are below 6 months old
• When holding the child, you may feel like he or she could slip right through your hands
• They are also unable to bend their elbows, knees, or hips

Other than type 1 SMA, hypotonia may also be seen in some other types of spinal muscle atrophy (SMA) such as type 2 and type 3.

2. Difficulty breathing and swallowing
Type 1 SMA generally affects people by destroying the motor neurons which are known to be extremely helpful for various muscle activities, such as swallowing or breathing. As a result, infants who are suffering from this condition find it quite problematic to breathe properly. Some of the children are also unable to drink milk or swallow it because of muscle weakness.

3. Difficulty sitting or moving
Because of the affected motor neurons, infants are unable to perform any normal motor function, such as moving or walking. Also, if an infant is affected severely, it might be quite difficult for him or her to sit properly without assistance. These symptoms are evident in some other types of spinal muscle atrophy (SMA).

4. Curvature of spine
The curvature of the spine or scoliosis is also quite common among infants who are suffering from type 1 SMA. This condition generally occurs in a much later stage of the disease when the spinal cord is severely damaged and is unable to bear the weight of the body. This condition may also occur among the other types of spinal muscle atrophy (SMA) if the affected person is not treated properly.

Among all the types of the disease, type 1 SMA is considered to be the most fatal. If the condition is not treated properly, the infant may also lose his or her life. Thus, most of the health specialists generally recommend parents to start proper treatment as soon as possible.