Research Paper On Muscular Dystrophy

1. The meaning of Duchenne muscular dystrophy is a severe form of muscular dystrophy caused by a genetic defect that can be characterized by a disturbed growth of cardiac and skeletal muscles. It usually affects boys. In 1861, a French neurologist, Guillaume B. Duchenne, was the first person to give a detailed description of this syndrome.

On very rare occasions when DNA studies do not present a clear picture a muscle biopsy may be required. A small piece of muscle tissue is taken with a needle, usually from the thigh. Using special staining techniques in the laboratory the muscle tissue is examined microscopically for dystrophin protein. In DMD, dystrophin is completely absent while in the related disorder Becker muscular dystrophy some dystrophin is present. Therefore, the muscle biopsy test is important in providing a definite diagnosis when DNA tests are inconclusive.

Duchenne muscular dystrophy (DMD) is a genetic disease that weakens one’s muscles. DMD is inherited through an X linked pattern due to the gene carrying the DMD mutation is on the X chromosome. The male population are affected by DMD almost exclusive. There is a one in two chance that a male offspring will have DMD if their mother is a carrier of the mutated gene. Every boy inherits an X chromosome from their mother and a Y from their father. If a boy inherits the mutated gene, then they will definitely have the disease because they don’t have a second gene to make up for the faulty one. Female with DMD are very rare in comparison to their counterpart. Girls inherits two X chromosomes, one from each parent. When a girl inherits

Muscular dystrophy (MD) is a genetic disorder caused by incorrect or missing genetic information that leads to the gradual weakening of the muscle cells. Various causes lead to weak and deteriorating muscles depending on the type of muscular dystrophy the patient was affected by. However, there are many causes for muscular dystrophy due to the fact that there are thirty forms of muscular dystrophy, which are categorized under several categories. All are ultimately caused by autosomal recessive, autosomal dominant, sex-linked, and random mutations in very rare cases.

Muscular dystrophy is a disease in which muscles become weak over time due to muscular atrophy. Duchenne and Becker

Muscular dystrophy (MD) is a group of genetically transmitted diseases characterized by progressive symmetric wasting of skeletal muscles without evidence of neurologic involvement (Lewis, 2011). There are four different types of muscular dystrophy. The four types are Duchenne, Becker, Landouzy-Dejerine, and Erb. Duchenne muscular dystrophy is the most common type among children. It only affects boys; it’s passed down from the mother. Duchenne muscular dystrophy is created from X-linked recessive gene from the mother. About one in thirty-five hundred boys are born with Duchenne muscular dystrophy. The boys will experience weakening of the muscles, wasting and contractures and inability to walk by themselves by the time they even reach

Muscular dystrophy is a hereditary condition marked by progressive weakening and wasting of the muscles. The main sign of muscular dystrophy is progressive muscle weakness. Specific symptoms start at different ages and in different muscle groups, depending on the type of muscular dystrophy. This disease can appear in infancy up to middle age or older. There are 9 major types of muscular dystrophy. Myotonic, Duchenne, Becker, limb-girdle, facioscapulohumeral, congenital, oculopharyngeal, distal, and emery-dreifuss. The diagnostic of muscular dystrophy can be found through a physical exam, family medical history, and tests. Furthermore, those include muscle biopsies, DNA testing, nerve conduction tests, and blood enzyme tests. Muscular dystrophy

The genetic disease known as Muscular Dystrophy first appeared in history in the year 1830. It was included in a written report by the Scottish Neurologist Sir Charles Bell. The disease soon became more prominent, where it appeared in several medical journals from the 1850’s and onwards. Several young boys were described as having a weakness which progressively worsened, along with problems walking. The disease led to their eventual premature deaths. A French Neurologist known as Guillaume Duchenne studied 13 boys who all had the most common and severe form of Muscular Dystrophy, soon to be known as Duchenne Muscular Dystrophy (NIH 2016). Muscular dystrophy refers to a group of more than 30 genetic diseases including Distal MD, Emery-Dreifuss MD, Facioscapulohumeral MD, Limb-girdle MD, Becker MD, Congenital MD, Myotonic MD and Oculopharyngeal MD. This review however will just focus on Duchenne muscular dystrophy.

Of all inheritable myopathies, central core disease accounts for 16 percent of cases. Nemaline Rod Myopathy accounts for 20 percent. 14 percent is Centronuclear myopathy. The last 10 percent is Multicore Myopathy. Prevalence of muscular dystrophy is higher in males. In the United States, Duchenne MD and Becker MD- result from a genetic defect on the X chromosome, which is why it occurs in approximately 1 in 3300 boys. 63 per 1 million is overall incidence of muscular dystrophy. Worldwide incidence of inflammatory myopathies is about 5–10 per 100,000 people. Women tend have these disorders more than men. Incidence and prevalence of endocrine and metabolic myopathies are unknown. Endocrine disorders tend to be more common in women so that's why Corticosteroid myopathy is the most common type of endocrine myopathy in women. Metabolic myopathies are rare, but diagnosis of these conditions is increasing in the United States.

Becker muscular dystrophy is a degenerative muscular disorder mainly affecting the voluntary muscles. This disease was named after the doctor who discovered it in the 1950s. BMD as it is called, affects the heart but not a severely as Duchenne muscular dystrophy. The symptoms of BMD usually start to affect the person during late childhood and adolescence. The first symptoms start with weakness in the legs and pelvis area , as well as the shoulders. It also affects the heart as the myocardium layer of heart muscle tissue slowly deteriorates. As the muscles become weaker, the patient may begin to waddle or walk on their toes to compensate for the weakness of the muscles. The respiratory system is usually the last system affected but eventually

2. What does consanguineous mean? Why is this concept especially important when discussing recessive genetic disorders?

Autosomal dominant for classical type. But EDS can also be inherited in autosomal recessive or x-linked fashion-

The four possible modes of inheritance include autosomal dominant, autosomal recessive, x-linked dominant, and x-linked recessive. With each P genotype being equivalent to the phenotypes of the female wild type and male mutant scarlet. However with each transition from P to F1 there are different outcomes. With autosomal dominant the F1 phenotype percent’s are 100% brick eye color for both male and female. With autosomal recessive the F1 phenotype percent’s are 100% scarlet for both male and female.

Part1) To understand and be able to complete a pedigree chart, one must be able to identify and be able to comprehend the genotypes being presented. Any child with a double recessive with have parents with either homozygous recessive and heterozygous, or heterozygous dominant and heterozygous dominant. Any child with a heterozygous genotype will have parents with, homozygous dominant and homozygous recessive, homozygous dominant and heterozygous dominant, homozygous recessive and heterozygous dominant. Any child with a homozygous dominant genotype needs to have parents who are, homozygous dominant and homozygous dominant, or homozygous dominant and homozygous recessive. A homozygous dominant and a heterozygous dominant will have the same phenotype,

Although the majority of disease are contained in recessive alleles, porphyria occurs in dominant alleles as well (Daempfle, 2016). The two forms of this disease are autosomal dominant pattern (AIP), and autosomal recessive patterns (congenital). The recessive pattern of porphyria may lay dormant within the carrier, and would require another donor with the recessive patterns before their offspring could exhibit the symptoms. However, if there are homozygous dominant or heterozygous alleles possessing porphyria then the