A Simple Guide to Spinal Muscular Atrophy, Diagnosis, Treatment and Related Conditions

This book describes Spinal muscular atrophy, Diagnosis and Treatment and Related DiseasesRecently a 5 month old Singapore boy diagnosed with Spinal muscular atrophy Type 1 will be able to obtain the $3 million Zolgensma single dose medicine treatment. This medicine is the most expensive medicine in the world. This is to be followed by a regime of Risdiplam costing $15, 000 for 64 days and possible steroids to prevent liver damage.
Spinal muscular atrophy is a genetic disorder featured by weakness and wasting (atrophy) in muscles utilized for movement (skeletal muscles). It is produced by a loss of specialized nerve cells termed motor neurons that regulate muscle movement. The weakness is likely to be more severe in the muscles close to the center of the body (proximal) compared to muscles away from the body's center (distal).
The muscle weakness normally becomes worse with age. There are many types of spinal muscular atrophy produced by alterations in the same genes. The types differ in age of start and severity of muscle weakness with overlap between the types. SMA type 0 (Congenital disease) - evident before birth and is the rarest of the SMASMA type I (Werdnig-Hoffmann disease) - affects babies less than six months old.
SMA type II (Dubowitz disease) - develops in babies between 7 and 18 months old. SMA type III (Kugelberg-Welander disease) - appears after 18 months of age. SMA type IV (Adult disease) - this type of SMA patients is diagnosed in adulthood. Other types of SMA and linked motor neuron diseases are caused by mutations in other genes such as:Spinal muscular atrophy that has progressive myoclonic epilepsy, Spinal muscular atrophy that has lower extremity predominance, X-linked infantile spinal muscular atrophy, andSpinal muscular atrophy that has respiratory distress type 1.
Congenital spinal muscular atrophy with arthrogryposis (persistent contracture of joints with fixed abnormal posture of the limb)Kennedy's disease, termed progressive spinobulbar muscular atrophy, may first be identified between 15 and 60 years of age. Distal spinal muscular atrophy (DSMA) a type of spinal muscular atrophy that mostly involves the hands, feet, lower arms, and lower legs. The symptoms of spinal muscular atrophy happen depending on the type of SMA present in the affected person, and the age the person acquires the genetic disorder:Weakness in muscles with sudden jolting movementsDifficulty in breathing and swallowing of foodIrregular shape of limbs, chest, spine due to a decrease in muscle strengthProblems with sitting, standing and walking normallyHigher risk of acquiring respiratory disorders and infectionsDiagnoses could be made by prenatal screening or by gene panel investigation and muscle biopsy.
Polymerase chain reaction (PCR) or multiplex ligation probe amplification (MLPA) can help to determine the homozygous exon 7 deletion in the SMN1 gene. The treatment has mainly been supportive in the pastPhysiotherapy-non-invasive ventilation, Airway clearanceGene TherapyStem Cell TherapyNew treatments have been produced that are combating the very poor morbidity and mortality linked with SMA I and II.
Zolgensma is a single dose intravenous injection gene therapy that allow the body to produce functioning SMN protein. All patients were alive at 20 months compared to expected 8% in other therapiesRisdiplam is an oral medicine that acts via modifying SMN2 splicing. Nusinersen is an intra-thecally delivered antisense oligonucleotide (ASO) that provides functional SMN2 formationTABLE OF CONTENTIntroductionChapter 1 Spinal muscular atrophyChapter 2 CausesChapter 3 SymptomsChapter 4 DiagnosisChapter 5 TreatmentChapter 6 PrognosisChapter 7 Muscle Atr...