Spinal Muscular Atrophy (SMA)
What You Need to Know
- Spinal muscular atrophy (SMA) is a disorder affecting the motor neurons—nerve cells that control voluntary muscle movement. These cells are located in the spinal cord.
- Because the muscles cannot respond to signals from the nerves, they atrophy — weaken and shrink — from inactivity.
- One in every 6,000 babies is born with SMA. It is one of the most prevalent genetic disorders affecting young children and a major cause of death in infancy.
- SMA can strike children at any age. SMA in infancy and early childhood is associated with worse outcomes, while patients who develop symptoms later in childhood or in adolescence usually have a more positive prognosis.
- SMA does not affect sensory nerves or intellect, but it has been observed that many patients with SMA are highly intelligent.
SMA Signs and Symptoms
Spinal muscle atrophy symptoms vary, and may be mild or disabling, but involve a weakness of the muscles that control movement. Involuntary muscles, such as those in the heart, blood vessels and digestive tract, are not affected.
SMA weakens the muscles closest to the center of the body, including the shoulders, hips, thighs and upper back. The affected child may develop a curve in the spine (scoliosis) due to loss of size and strength of the back muscles.
Progression of SMA can also affect breathing and swallowing, which can threaten the life of the patient.
SMA Causes and Risk Factors
Spinal muscle atrophy is a genetic disorder. Most forms of SMA are caused by mutations of the survival motor neuron 1 gene (SMN1) on the fifth chromosome, resulting in insufficient expression levels of the SMN protein.
SMN is essential to normal motor function because it enables muscles to receive signals from the nerves.
New Hope for Patients with SMA
Patients with spinal muscular atrophy, or SMA, live in hope of simply standing or sitting upright. But neuromuscular disease specialist Charlotte Sumner says, “We are closer to a treatment for SMA than for perhaps any other inherited neuromuscular disorder."
Types of SMA
Spinal muscle atrophy is classified as type 1, 2, 3 or 4 depending on age of onset. Most cases are progressive — that is, symptoms worsen instead of improving – but in general the later the symptoms develop, the better the outcome for motor function.
SMA type 1 (infantile-onset SMA or Werdnig-Hoffman disease): This is the most severe kind of SMA and strikes infants within the first six months of life. Some children with SMA type 1 will die before their second birthday, but aggressive therapy is improving the outlook for these children.
SMA type 2 (intermediate SMA): When a child develops spinal muscular atrophy between six and 18 months, the condition is classified as type 2. The child may be able to sit up, but respiratory challenges can shorten their lives as the disease progresses.
SMA type 3 (juvenile SMA, Kugelberg Welander syndrome): Type 3 SMA emerges in children 18 months old or older and can become evident as late as in the teenage years. Muscle weakness is present, but most patients can walk and stand for limited periods, particularly early in the course of the illness.
SMA type 4 (adult SMA): In some people, SMA develops in adulthood. Type 4 SMA is rarely severe enough to have impact on the patient’s lifespan .
SMA not linked to chromosome 5: Some forms of SMA are not due to SMN1 gene mutations and SMN protein deficiency. These forms, including Kennedy’s disease, vary in severity, and some may involve muscles farther away from the center of the body than those associated with SMA types 1 through 4.
The symptoms of spinal muscle atrophy are similar to those of a number of other diseases affecting the muscles. To determine whether a patient’s muscle atrophy is due to SMA, the doctor may use the following tests:
Strength Under Pressure
Tom Crawford has a long history of caring for children with SMA. He has treated more than 325 patients and participated in the discovery of the SMA gene, testing new treatments and developing care guidelines. Currently, he’s working to standardize an approach to test the impact of experimental therapies for SMA—and he’s making it entertaining.
Treating and Managing SMA
At present, there is no cure for SMA. Those affected by the disorder can work with their health care providers to manage SMA symptoms and prevent complications, which can contribute to quality of life.
Among the approaches that may be recommended:
- Medication: There are no current medications for treatment of spinal muscular atrophy. Several medications to improve muscle and nerve function are currently in clinical trials.
- Braces, support devices and wheelchairs: These can help patients maintain their independence as long as possible.
- Physical and occupational therapy and rehabilitation: In addition to therapy to keep joints flexible and to slow the progression of muscle wasting while improving flexibility and circulation,specific therapies for speech, chewing and swallowing may be appropriate. Proper feeding is essential to avoid aspiration (inhaling food or fluid into the lungs) and ensure good nutrition.
- Ventilation assistance: Patients with breathing difficulties may require non-invasive ventilation to prevent apnea while sleeping, while others may need assisted ventilation during the daytime as well.
Sofia was born with SMA and treated with a revolutionary gene-targeting therapy. These therapies, while not a cure, have demonstrated new measurable motor milestones, such as head control, sitting, crawling and even standing.
Spinal Muscular Atrophy (SMA) ni ugonjwa unaosababisha misuli ya misuli ya mshipa wa mgongo (MMS) ambayo huathiri misuli ya misuli ya misuli. Chembe hizo ziko katika uti wa mgongo. - Kwa sababu misuli haiwezi kujibu ishara kutoka kwa neva, hufifia <unk> kudhoofika na kupungua <unk> kutokana na kutofanya kazi. Kila mtoto wa kwanza kuzaliwa ana ugonjwa wa SMA. Ni mojawapo ya magonjwa ya urithi yanayowaathiri watoto wadogo na ni mojawapo ya sababu kuu za vifo vya watoto wachanga. SMA inaweza kuwa na athari kwa watoto wa umri wowote. Ugonjwa wa SMA katika utoto na utotoni una uhusiano na matokeo mabaya zaidi, wakati wagonjwa ambao huendeleza dalili baadaye katika utotoni au katika ujana kwa kawaida huwa na utabiri mzuri zaidi. SMA haathiri neva za hisia au akili, lakini imeonekana kwamba wagonjwa wengi wenye SMA ni wenye akili sana. Dalili za ugonjwa wa mshipa wa mgongo (SMA) ni tofauti, na inaweza kuwa nyepesi au kuharibu, lakini inahusisha udhaifu wa misuli inayodhibiti harakati. Misuli isiyo ya hiari, kama vile ile iliyo katika moyo, mishipa ya damu na mfumo wa kumeng'enya chakula, haathiriwi. SMA huathiri misuli iliyo karibu na mwili, ikiwa ni pamoja na mabega, viuno, viuno na mgongo. Mtoto aliyeathiriwa anaweza kuwa na mviringo katika uti wa mgongo (skoliosis) kwa sababu ya kupoteza ukubwa na nguvu ya misuli ya mgongo. Kuendelea kwa ugonjwa wa SMA pia kunaweza kuathiri kupumua na kumeza, jambo ambalo laweza kuhatarisha uhai wa mgonjwa. Ugonjwa wa spinal muscular atrophy (SMA) ni ugonjwa wa urithi. Aina nyingi za SMA husababishwa na mabadiliko ya jeni la survival motor neuron 1 (SMN1) kwenye kromosomu ya tano, na kusababisha viwango vya kutosha vya uonyesho wa protini ya SMN. SMN ni muhimu kwa utendaji wa kawaida wa motor kwa sababu inawezesha misuli kupokea ishara kutoka neva. Kwa mfano, wagonjwa wa SMA (spinal muscular atrophy) wanaishi kwa matumaini ya kusimama au kukaa wima. "Mtaalamu wa magonjwa ya neva na misuli, Charlotte Sumner, anasema: ""Tumekaribia kupata tiba ya ugonjwa wa SMA kuliko ya ugonjwa mwingine wowote wa neva na misuli." Aina ya SMA: Spinal Muscle Atrophy (SMA) ni aina ya kwanza, ya pili, ya tatu na ya nne kulingana na umri wa mwanzo. Matukio mengi ni ya maendeleo - yaani, dalili huzidi kuwa mbaya badala ya kuboresha - lakini kwa ujumla dalili zinapoendelea baadaye, matokeo ni bora kwa kazi ya gari. Aina ya kwanza ya SMA (Ugonjwa wa Werdnig-Hoffman) ni ugonjwa wa watoto ambao huanza katika miezi sita ya kwanza ya maisha. Watoto walio na SMA ya aina ya 1 hufa kabla ya miaka yao ya pili ya kuzaliwa, lakini matibabu ya haraka yanaongeza matarajio ya watoto hao. Aina ya 2 (Intermediate) - Ikiwa mtoto ana ugonjwa wa spinal muscular atrophy kati ya miezi sita na kumi na nane, ugonjwa huo huitwa aina ya 2. Huenda mtoto akaweza kuketi, lakini matatizo ya kupumua yaweza kufupisha maisha yake kadiri ugonjwa unavyoendelea. Aina ya 3 (JUVENILE SMA, KUGELBERG-WELANDER SYNDROME) ni ugonjwa wa watoto wenye umri wa miezi 18 na zaidi ambao huanza kuonekana katika miaka ya ujana. Ugonjwa wa misuli ni wa kawaida, lakini wagonjwa wengi wanaweza kutembea na kusimama kwa muda mfupi, hasa mapema katika ugonjwa. Aina ya 4 (SMA ya watu wazima): Katika watu wengine, SMA huanza wakati wa utu uzima. Aina ya 4 ya SMA ni hatari sana kwa afya ya binadamu na inaweza kuathiri maisha ya mgonjwa. Aina fulani za SMA hazihusiani na mutations ya jeni SMN1 na upungufu wa protini SMN. Aina hizi, ikiwa ni pamoja na ugonjwa wa Kennedy, hutofautiana katika ukali, na baadhi yaweza kuhusisha misuli iliyo mbali zaidi na katikati ya mwili kuliko ile inayohusishwa na aina za SMA 1 hadi 4. Dalili za kupungua kwa misuli ya uti wa mgongo zinafanana na zile za magonjwa mengine mengi yanayoathiri misuli. Kwa mfano, kwa mfano, kwa ajili ya uchunguzi wa ugonjwa wa SMA, daktari anaweza kutumia vipimo vifuatavyo: Ameshughulikia wagonjwa zaidi ya 325 na ameshiriki katika ugunduzi wa jeni la SMA, kujaribu matibabu mapya na kuendeleza miongozo ya utunzaji. Hivi sasa, yeye ni kazi ya standardize mbinu ya mtihani wa athari ya matibabu ya majaribio kwa SMA na yeye ni kufanya hivyo burudani. Matibabu na Usimamizi wa SMA Kwa sasa, hakuna tiba ya SMA. Wale walioathiriwa na ugonjwa huu wanaweza kufanya kazi na watoa huduma zao za afya kusimamia dalili za SMA na kuzuia matatizo, ambayo yanaweza kuchangia ubora wa maisha. Miongoni mwa mbinu zinazoweza kupendekezwa ni: - Dawa: Hakuna dawa za sasa za kutibu atrophy ya misuli ya uti wa mgongo. Dawa kadhaa za kuboresha utendaji wa misuli na neva kwa sasa zinafanyiwa majaribio ya kliniki. - Vifaa vya kuegesha, vifaa vya kutegemeza na viti vya magurudumu: Vitu hivyo vinaweza kuwasaidia wagonjwa kudumisha uhuru wao kwa muda mrefu iwezekanavyo. - Tiba ya kimwili na kazi na ukarabati: Mbali na tiba ya kuweka viungo rahisi na kupunguza maendeleo ya kupoteza misuli wakati wa kuboresha kubadilika na mzunguko, matibabu maalum kwa ajili ya hotuba, kutafuna na kumeza inaweza kuwa sahihi. Kulisha vizuri ni muhimu ili kuepuka kutamani (kuingiza chakula au umajimaji ndani ya mapafu) na kuhakikisha lishe nzuri. - Msaada wa kupumua: Wagonjwa wenye matatizo ya kupumua wanaweza kuhitaji kupumua bila uvamizi ili kuzuia apnea wakati wa kulala, wakati wengine wanaweza kuhitaji kupumua kwa kusaidiwa wakati wa mchana pia. Sofia alizaliwa na ugonjwa wa SMA na kutibiwa kwa tiba ya kiuchumi ya kulenga jeni. Tiba hizi, ingawa si tiba, zimeonyesha hatua mpya za kuweza kupimwa za utendaji wa mwili, kama vile kudhibiti kichwa, kukaa, kutambaa na hata kusimama.