The Sickle-Cell Disease Genetics Mutation

Understanding the genetics and how we are built on a blueprint containing thousands and thousands of variant codes is something that the science still has much to learn about. Especially when it comes to understanding mutations and the effects that it consequently has on someone’s development and life. In this case we will discuss the research of sickle cell. Sickle cell affects about 70,000-100,000 Americans. Approximately 3,000,000 are a carrier of the trait. Sickle cell is a genetic disorder ( Recessive; 2 abnormal cells are needed to show this trait) that affects the hemoglobin in red blood cells.

It is a disease in which the mutation occurs in the codon sequence. Occurring in the amino acid sequence located at the 6th position of a beta-protein chain; out of 146. Hemoglobin consists of two protein chains two alpha and two beta. When there is a mutation in the globin gene that alters the protein build up, but not exactly the amount of assertion, in other words it is a qualitative mutation.

A mutation in the B-globin gene can have a higher chance of causing sickle cell anemia. This is the most common form. This change, a form of mutation called a missense, morphs a glutamic acid codon into a valine codon.

People that inherit this trait for sickle cell that have the allele for hemoglobin are HbS. Normal adults with healthy hemoglobin are referred to as HbA2. The heterotetramer for HbA2 has the genetic build up of two a-globin peptides, this also including two o-globin peptides.

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The b-globin gene cluster has many genes where their 5’ to 3’ orientation on chromosome number; 11 reflecting ontogeny of their expression from embryonic hemoglobin, to where adult b-globin (the delta gene weakly follows with the b gene). The b-globin gene is located at the 11p15.5 region and is composed of 3 exons; this encodes 146 amino acid proteins. The valine in for glutamic acid substitution has results that show hemoglobin tetramers that aggregate into arrays upon deoxygenation in the tissues. This Leads to distortions in the RBC’s resulting in a concaved, Moon like, shaped like cell.

The main article referenced speaks on how treatment with hydroxyurea has an effect with raising hemoglobin with hydroxyurea (A chemo drug that helps with Chronic myelomonocytic leukemia; CMML) on organ damage and survival. The second article that is referenced speaks on how ZBTBB7A hypomethylation and expressed patterns respond to these types of treatments. With our final reference is an article that speaks on KLF1 fetal globin repressor ZBTB7A/LRF and it’s activated expression of the erythroid cells.

Experimental Approach/Results

Some of the methods implemented by the experimenters in the article from the primary source was getting first a patient population. Subjects had to be enrolled for screening studies to commence. This study would take place from 2001-2012. Subjects were 18+ and must have been diagnosed with sickle cell disease. Every two years clinical, hematology, and ECG’s were performed as well as mortality data was collected. Death certificates were collected for that part. 383 subjects were enrolled and were averaged at the age of 31 (range of 18-74years old) with evenly divided gender proportions to ever been treated with hydroxyurea. Medians follow up was 2.6. 59 people that were used for this experiment; (15%) deceased at the average age of 46 for men and 44.5 for women.

These People experienced symptoms that were fairly similar to each other but all passed away of different causes. Sickle cell disease phenotypes were chosen and paired based on DNA sequencing and/or high performance liquid chromatography. Mean corpuscular volume was evaluated in all participants due to its increase in response with hydroxyurea. Maximum HbF and MCF were defined as the mean and was calculated from these values. Treatment and dosing of hydroxyurea exposure was at the wariness of each subjects’ primary provider. Computer assisted review assisted with review of documentation by words of “hydroxyurea” and synonyms. If exposure was made (positive) then documentation was recorded. Duration of treatment is undetermined using the same records