Biology

Chromosomal abnormalities pertain to rearrangements that generate alterations in the normal karyotype of cells.  There are two general kinds of chromosome abnormalities, based on the site of occurrence of the rearrangement.  Constitutional chromosomal abnormalities commonly occur in all of the cells of the human body, while acquired chromosomal abnormalities are observed only in specific tissues.  In addition, there are also two categories of chromosomal abnormalities that are based on the nature of the rearrangement.  Numerical chromosomal abnormalities pertain to a change in the number of chromosomes in each cell, while structural abnormalities refer to the rearrangements of specific chromosomal segments within the genome.

One common constitutional chromosomal rearrangement that involves a change in the total number of chromosomes in a cell is Klinefelter syndrome.  This condition involves the presence of a third sex chromosome in each cell, thus generating a constitutional karyotype of 47,XYY.  In a normal cell, there are 46 chromosomes, of which are comprised of 44 somatic chromosomes and 2 sex chromosomes, of which can either be XX or YY.  The sex of an individual is thus mainly based on the combination of sex chromosome in the cells.  Females therefore carry cells that carry the two X chromosomes (XX), while males carry cells that have one X and one Y chromosome (XY).

In the case of Klinefelter syndrome, all the cells of the body have 47 chromosomes and this is mainly due to an extra Y chromosome.  Individuals diagnosed with Klinefelter syndrome are usually thin and tall, as well as seldom develop breast during puberty (Dutta et al., 2009).  These individuals are also incapable of producing sperm, as the reproductive organs are often affected by the presence of an excess sex chromosome in all cells.  The main external reproductive features of an individual with Klinefelter are thus characterized to be female, yet the individual is incapable of ovulating and producing eggs for fertilization.

Klinefelter syndrome is usually diagnosed post-natally through karyotyping.  This assay technically involves extraction of a blood sample from the individual and subjecting this specimen to cell culture.

The lymphocytes in the blood are induced to undergo mitosis through the introduction of a mitogen, after which chromosomes could be prepared after 3 days of cell culture.  It is also possible to diagnose Klinefelter syndrome prenatally through either amniocentesis or chorionic villi sampling, yet this procedure is not commonly performed if no pregnancy risk factors have been identified in the mother.
One psychosocial issue associated with Klinefelter syndrome is the dilemma of whether the diagnosed individual should be treated as a male or a female.  Physically, an individual diagnosed with Klinefelter syndrome can be classified as female because of the presence of female reproductive body parts.  However, the presence of a Y chromosome in all the cells of the individual dictates that the individual is genetically male.  There is also an association between mental retardation and Klinefelter syndrome and thus social interactions with other individuals may be more difficult than that with normal, healthy individuals.

One ethical issue associated with Klinefelter syndrome is when the developing fetus is diagnosed prenatally and the mother is given the option to proceed with the termination of the pregnancy.  Klinefelter individuals are capable of developing into an almost normal individual, despite the incapability of producing offspring when they reach adulthood.  It is thus considered unethical to conduct an abortion if the main basis for the termination is Klinefelter syndrome, as this condition is not life threatening either to the fetus or the pregnant mother.  

Acute myeloid leukemia pertains to an acquired genetic chromosomal abnormality that is only observed among leukemic cells.  The chromosomal rearrangement involved in this disease could be microscopically detected, yet additional information could also be generated through molecular biology tools.  An individual positively diagnosed with acute myeloid leukemia is commonly observed with a translocation between chromosomes 8 and 21 or chromosome 16 concurring with an inversion within the same chromosome.  These two kinds of chromosomal rearrangements determine the prognosis of the patient during treatment.

One common nature of acquired chromosomal abnormalities is the occurrence of at least two types of rearrangements with the leukemic cells.  This mosaicism occurs in almost of cases of acute myeloid leukemia, rendering the design of treatment options more complicated than a simple causative factor that involves a single gene.  It is thus important to determine the type and extent of the chromosomal rearrangements that are occurring in the leucocytes of the patient.

Acute myeloid leukemia is generally diagnosed by chromosomal analysis.  Briefly, the bone marrow is extracted from the patient and subjected to culture conditions through the introduction of a mitogen that would stimulate cell division.  Similar to the methodology involved in the karyotypic diagnosis of Klinefelter, the chromosome extracted from the bone marrow cells would be analyzed based on the results of chromosome banding.

Since acute myeloid leukemia is an acquired chromosomal abnormality, variations in chromosomal rearrangements significantly vary, depending on the clonal source of the aberrations.  It is thus important for cytogeneticists to analyze a significant number of cells in the laboratory in order to determine as many variations in rearrangements.  There are also cases wherein a patient with acute myeloid leukemia does not have any chromosomal rearrangements in any of his cells.  Karyotypic results are of prime importance in the design of treatment options and thus its absence would impact the entire treatment and prognosis of the patient.  During treatment of acute myeloid leukemia patients, regular karyotypic checks are performed to document remission.

One of the psychosocial issues associated with acute myeloid leukemia is the impact of the shortened life span of the patient.  A diagnosis of acute myeloid leukemia is often linked with the development of depression, as the patient feels that he is hopeless in terms of getting better and that his number of years to live is significantly shorter.  The family members of the patient are also affected, as they fear and are saddened by the idea that they could lose their loved one at any moment in the near future.
The progression of acute myeloid leukemia results in a patient that has lost most of his strength and thus will be contained within the hospital during the last few weeks of his life.  One ethical issue that is associated to this disease is euthanasia, which involves the request of the patient for the administration of a lethal of dose of a drug in order to prevent his further suffering.  It should be understood that euthanasia is practiced in certain states in United States, as well as a number of countries around the world.  Euthanasia is often the resorted option of patients who are experiencing a tremendous amount of pain that could not be alleviated by the strongest medications that are available in the hospital.  This physician-assisted form of death is also considered as a right of the patient, as each human being has the right to choose what type of healthcare should be delivered to him.  If a physician does not follow the request of the patient, then the case would be that of paternalism, which is characterized by the domination of a physicians choices with regards to the kind of treatment to be delivered to the patient.