Alzheimer’s is a neuro-degenerative disorder of the brain that results to changes in normal functioning. Discovered by Alois Alzheimer in 1906, the disease usually affects individuals in their late stages in life as from the age of 65 years. Researchers, however, state that individuals with as early as 30 years can be diagnosed since initial observation by Dr. Alzheimer was conducted on a fifty one year old woman who experienced changes in her behaviour. The problems she experienced included, memory failure, difficulties while speaking and lack of comprehension. Due to the abnormal symptoms identified, the doctor, after carrying an autopsy discovered that the cerebral cortex had a contraction, there were fatty deposits in the blood vessels and the brain cells had emaciated. Alzheimer was thus in 1910 credited as the founder of this disease after a medical literature congregation in 1907 that decided that the disease be named after him (Jimenez, Bartels, Cardenas, Dhaliwal and Alegria 534 – 536).
The early cases of Alzheimer’s disease don’t have a specific cause but others are classified as inherent. This inherent type of Alzheimer’s disease is caused by varied single-gene mutations on chromosomes which result to the formation of abnormal proteins. The mutations on chromosomes resulted in formation of abnormal amyloid precursor protein. Traits witnessed by observing patient of Alzheimer’s disease are as an effect of the malfunction of the phenotype which not dominant. It is conversely apparent that the levels of molecular factors of the disease are dominantly expressed. Therefore, this proves that functional protein is not encoded by the disease allele in cases of recessive genetic diseases. Though the cells are able to work effectively and normal destruction happens regularly, on numerous occasion their operation are altered and the results on this occasions are ineffective. In such cases, the traits are highly competent since the gene has multiple effects on the central nervous system leading to disorders such as those witnessed in Alzheimer’s (Gray, Jimenez, Cucciare, Tong and Gallagher-Thompson 925 – 927).
The important difference of δ and β genes is the time of expression. In this mixture of genes the authoritarian section occupied by the β gene can be substituted with the narrow information of the δ gene, therefore the hybrid gene may be expressed inappropriately. Successful mutation should state identifiable phenotype that signifies transcription and moderation of the efficiency of the gene. Mutations compliment each other when different genes are required for a phenotype.
Case studies on the Alzheimer’s disease have proved that it is hereditable and sporadic. The sporadic cases have been linked to the apoliprotein E gene that is present in chromosome 19 which takes varied alleles and is tasked with carrying cholesterol in the blood vessels. Individuals inherit an allele from the three apoliprotein E gene that are mainly, apoliprotein E 2, 3 and 4. The chances of acquiring Alzheimer’s disease depends on the copies of apoliprotein E4 allele one has since it’s the risk factor for this disease (Napoles, Chadiha, Eversley and Moreno-John 390). It has however been established that individuals who don’t develop apoliprotein E4 acquire Alzheimer’s while those with two copies of the gene do not develop the disease. Individuals with apoliprotein E2 allele hardly develop the infection making it as the determinant in categorizing the disease.
In chromosome 21’s long arm we have amyloid precursor protein which facilitates the formation of the brain tissues in adults. Loss of one protein due to mutation will prevent all the ensuing proteins from addition. The loss of the first protein would prevent all others from staying at the cell surface (Feng, Fennell, Tyler, Clark and Mor 1359). This type of protein undergoes six diverse mutations which cause the advancement of Alzheimer’s disease. This mutation occurs on a particular gene indicating that this progression is more effective when done on a definite location. Results of this kind of mutations represent approximately 20% of Alzheimer’s diseases. This further directs to the growth of the amyloid of the brain.
The diagram shows the Amyloid precursor protein pathway
- APP- represents the main protein in Alzheimer’s transmembrane amyloid precursor protein
- β-secretase- different forms of the protein generated by alternative
- 695 -amino acid
- sAPPβ -large soluble n-terminal fragment
- Met-596 -sequential cleavage of APP that produce Amyloid β (Aβ)
- 40, 42 or 43 – Aβ isoforms of amino acids designated x-40, x-42 or x-43
- X-40, x-42 and x-43- levels of Aβ peptides Progression of Alzheimer’s disease
Works Cited
Feng, Z., Fennell, M. L., Tyler, D. A., Clark, M., and Mor, V. The care span: Growth of racial and ethnic minorities in US nursing homes driven by demographics and possible disparities in options. Health Affairs, 30(7)(2011), 1358–1365. doi:10.1377/hlthaff.2011.0126
Gray, H. L., Jimenez, D. E., Cucciare, M. A., Tong, H. Q., and Gallagher-Thompson, D. Ethnic differences in beliefs regarding Alzheimer disease among dementia family caregivers. American Journal of Geriatric Psychiatry, 17(11) (2009), 925–933. doi:10.1097/JGP.0b013e3181ad4f3c
Jimenez, D. E., Bartels, S. J., Cardenas, V., Dhaliwal, S. S., and Alegria, M. Cultural beliefs and mental health treatment preferences of ethnically diverse older adult consumers in primary care. American Journal of Geriatric Psychiatry, 20(6)(2012), 533–542. doi:10.1097/JGP.0b013e318227f876
Napoles, A. M., Chadiha, L., Eversley, R., and Moreno-John, G. Reviews: developing culturally sensitive dementia caregiver interventions: Are we there yet? American Journal of Alzheimer’s Disease and Other Dementias, 25(5)(2010), 389–406. doi:10.1177/1533317510370957