SMA is a hereditary neuron disease that affects the central nervous system and skeletal muscle system. SMA, a rare disease, usually affects infants and children. There is no definitive treatment method for SMA, which is the most talked about health problems recently.

SMA, also known as Loose Syndrome among the people, can cause children to lose their lives in our country as well as in the world.


SMA (spinal muscular atrophy) affects the motor nerve cells in the spinal cord, eliminating the ability to walk, eat or breathe. For babies, genetics is the number one cause of death. SMA is caused by a mutation in the survival engine neuron gene 1 (SMN1).

In a healthy person, this gene produces a protein muscle is critical for the function of the nerves that control our muscles. Without it, these nerve cells cannot function properly and eventually do not die, which leads to debilitating and often fatal muscle weakness.

According to the age of onset and the highest physical milestone achieved, there are four main types of SMA: I, II, III and IV.

Spinal muscular atrophy (SMA) is not just a condition, it is a set of diseases. Grouped together, different types of SMA constitute the second leading cause of neuromuscular disease.

SMA is found in 1 in every 6,000 to 10,000 live births. It is the second most common fatal autosomal recessive disease after cystic fibrosis.

Individuals with SMA have difficulty performing basic functions of life, such as breathing and swallowing. However, SMA does not affect a person’s ability to build relationships with others, think and learn.


Most SMA types are caused by a problem with a gene called the SMN1 gene. The gene does not make enough of a protein needed for motor neurons to function normally. Motor neurons break down and cannot send signals to muscles.

A child with SMA receives a copy of the SMN1 gene from each parent. A child who receives the SMN1 gene from only one parent probably does not show any signs of SMA, but can pass the gene on to their child.

Genetic tests of people with SMA and their parents can help determine the likelihood that someone will have a child with SMA.


The four types of SMA are classified according to the severity of the disease and the age at which the symptoms began:

Type I is sometimes referred to as infantile-onset SMA or Werdnig-Hoffmann’s disease. Type I begins to affect babies up to 6 months from birth, most babies show signs of the disease at 3 months of age. This is the most severe form of SMA.

Type II begins to affect children aged 7-18 months. Children can sit independently, but not walk. This form can be moderate to more severe.

Type III, also called Kugelberg-Welander syndrome or children’s SMA, begins to affect children at the age of 18 months or as early as adolescence. Children can walk independently, but there is weakness in their arms and legs, and they can often fall over. This is the mildest form of SMA in children.

Type IV is the adult form of SMA. Symptoms usually begin after the age of 35 and gradually worsen over time. Because it develops slowly, many people with type IV SMA don’t know they have SMA until years after symptoms start.


Symptoms of SMA depend on its severity and the age of the person when it begins. Babies SMA type I are born with very little muscle tone, weak muscles, and problems with nutrition and breathing. With SMA type III, symptoms may not appear until the second year of life.

All its forms, the main feature of SMA is muscle weakness, which is accompanied by muscle atrophy. This is the result of the loss of the signal to denervate or contract, which is transmitted through the spinal cord.

This signal is normally transmitted from the motor neurons in the spinal cord to the muscles via the axon of the motor neuron. In SMA, the axonated motor neuron or the axon itself becomes inoperative. It stops working.

Most of the symptoms of SMA are related to secondary complications of muscle weakness. These can be partially alleviated by therapy.


There is no cure for SMA yet, and since it is an inherited condition, there is no way to prevent it. However, treatment can help people live fuller lives.


In 2016 the Food and Drug Administration (FDA) of the United States (USA) approved nusinersen (Spinraza), a drug to treat SMA. It is the first drug approved for this condition.

Spinraza targets the underlying damage in SMA so that it can help delay, prevent, and even reverse symptoms. Among the common side effects the risk of respiratory tract infection and constipation. There may also be a risk of bleeding and kidney problems.

Auxiliary devices

Assistive technologies such as ventilators, electric wheelchairs, and modified access to computers allow people with SMA to live longer, be more active, and participate in society.

Ventilation is especially important. The severity of the individual’s weakness directly affects the course of the disease. Infants severe SMA may have respiratory disease because the muscles that support breathing are weak.

Children with milder forms of SMA can expect to have a longer lifespan, but they may need extensive medical support.

Molecular biology has improved our understanding of SMA. Many experimental treatments are being tested, including gene replacement, stem cell replacement of motor neurons, and therapies to increase the expression of the SMN 2 gene.


Parents with a family history of SMA are advised to seek genetic counseling before starting a family.

The most fatal is the stage with Type I.


Follow me
President of Organ Transplant Center at MedicalPark Hospital Antalya

Turkey's world-renowned organ transplant specialist. Dr. Demirbaş has 104 international publications and 102 national publications.

Physician's Resume:

Born on August 7, 1963 in Çorum, Prof. Dr. Alper Demirbaş has been continuing his work as the President of MedicalPark Antalya Hospital Organ Transplantation Center since 2008.

Prof. who performed the first tissue incompatible kidney transplant in Turkey, the first blood type incompatible kidney transplant, the first kidney-pancreas transplant program and the first cadaveric donor and live donor liver transplant in Antalya. Dr. As of August 2016, Alper Demirbaş has performed 4900 kidney transplants, 500 liver transplants and 95 pancreas transplants.

In addition to being the chairman of 6 national congresses, he has also been an invited speaker at 12 international and 65 national scientific congresses. Dr. Alper Demirbaş was married and the father of 1 girl and 1 boy.


Eczacibasi Medical Award of 2002, Akdeniz University Service Award of 2005, Izder Medical Man of the Year Award of 2006, BÖHAK Medical Man of the Year Award of 2007, Sabah Mediterranean Newspaper Scientist of the Year Award of 2007, ANTIKAD Scientist of the Year Award of 2009, Social Ethics Association Award of 2010, Işık University Medical Man of the Year Award of 2015, VTV Antalya's Brand Value Award of 2015.


Doctor of Medicine Degree Hacettepe University Faculty of Medicine Ankara, General Surgeon Ministry of Health Turkey EKFMG (0-477-343-8), University of Miami School of Medicine Member of Multiple Organ Transplant, ASTS Multiorgan Transplant Scholarship. Lecturer at Kyoto University. Lecturer at University of Essen, Research assistant at the University of Cambridge .

Professional Members:

American Society of Transplant Surgeons, American Transplantation Society Nominated, Middle East and Southern Africa Council Transplantation Society 2007, International Liver Transplantation Association, Turkish Transplantation Association, Turkish Society of Surgery, Turkish Hepatobiliary Surgery Association.


Our website contents consist of articles approved by our Web and Medical Editorial Board with the contributions of our physicians. Our contents are prepared only for informational purposes for public benefit. Be sure to consult your doctor for diagnosis and treatment.
Medically Reviewed by Professor Doctor Alper Demirbaş
Follow me
Latest posts by Medically Reviewed by Professor Doctor Alper Demirbaş (see all)