Sickle trait

Sturgeon, P., Itano, H. A., and Valentine, W. N., Chronic hemolytic anemia associated with thalassemia and sickling traits. Blood 7, 350-357 (1952). 

An adolescent presents with shortness of breath during exercise and is found to be anemic. A hemoglobin electrophoresis is performed that is depicted in the figure below. The adolescents sample is run with controls including normal, sickle trait, and sickle cell anemia, and serum. The adolescent is determined to have an unknown hemoglobinopathy. Which one of the lanes contains the adolescent s sample ... 

The answer is e. (Murray, pp 812-828. Scriver, pp 3-45. Sack, pp 97-158. Wilson, pp 59-78.) The African American man and woman each have a 1/8 chance of having sickle trait. They have a 1/64 x 1/4 = 1/256 chance of having a child with sickle cell anemia. There is also a 1/64 X 1/2 = 1/128 chance that their child will have sickle trait. 

Screening of an African American population in Minnesota yields allele frequencies of 7/8 for the A globin allele and 1/8 for the sickle globin allele. A companion survey of 6400 of these people s ancestors in central Africa reveals 4600 individuals with genotype AA, 1600 with genotype AS (sickle trait), and 200 with genotype SS (sickle cell disease). Compared to their descendants in Minnesota, the. Alrican population has... 

Ayi, K., Turrini, F., Piga, A., and Arese, P. (2004). Enhanced phagocytosis of ring-parasitized mutant erythrocytes a common mechanism that may explain protection against falciparum malaria in sickle trait and beta-thalassemia trait. Blood 104,3364—3371. 

Patients with sickle trait have fewer symptoms than those with sickle disease. 

Milosevic M, Quirt I, Levin W, Fyles A, Manchul L, Chapman W (2001b) Intratumoral sickling in patient with cervix cancer and sickle trait Effect on blood flow and oxygenation. Gynecol Oncol 83 428-431... 

Electrospray mass spectra of globins from the blood of (a) a child diagnosed as having the sickle-cell anemia trait and (b) of its mother. As well as the usual p-globin sickle-cell variant at m/z 15,837.2, a new variant (P-Montreal-Chori) appears at m/z 15,879.3 and is observed in both the child and the mother. 

In certain reglon.s of Africa, tire. sickle-cell trait Is found In 20% of the people. Wiry does snch a deleterious heritable condition persist in dre popnladon For reasons as yet unknown, individnals widr this trait are less sn.scepdble to dre most virnlent form of malaria. The geographic distribn-don of malaria and dre sickle-cell trait are posidvely correlated. 

The detection of restriction fi agment length polymorphisms (RFLPs) facilitates prenatal detection of hereditary disorders such as sickle cell trait, beta-thalassemia, infant phenylketonuria, and Huntington s disease. Detection of RFLPs involves cleavage of double-stranded DNA by restriction endonucleases, which can detect subtle alterations in DNA that affect their recognized sites. Chapter 40 provides further details concerning the use of PCR and restriction enzymes for diagnosis. 

Figure 7. Microchromatography on DEAE-cellulose. A, The levels of Hb-At in normal adults, in p thalassemia heterozygotes, in Hb S traits, and in patients with sickle cell anemia and HbS-p-thalassemia (Georgia survey). B, The levels of Hb-At in normal adults and in p-thalassemia heterozygotes (Macedonia survey).

O Sickle cell disease is an inherited disorder caused by a defect in the gene for hemoglobin. Patients may have one defective gene (sickle cell trait) or two defective genes (sickle cell disease). 

Sickle cell trait (SCT) is the heterozygous form (HbAS) of SCD in which a person inherits one normal adult hemoglobin (HbA) gene and one sickle hemoglobin (HbS) gene. These individuals... 

FIGURE 65-1. Sickle gene inheritance scheme for both parents with sickle cell trait (SCT). A, normal hemoglobin S, sickle hemoglobin. Possibilities with each pregnancy 25% normal (AA) 50% SCT (AS) 25% sickle cell anemia (SS). (From Chan CYJ, Moore R. Sickle cell disease. In DiPiro JT, Talbert RL, Yee GC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill 2005 1856.)... 

TABLE 65-1. Clinical Features of Sickle Cell Trait and Sickle Cell Disease... 

Mother with sickle cell trait father with sickle cell disease. Father died at age 36 from stroke. Has an older brother with SCD and a younger sister with SCT. 

The most common abnormal hemoglobin in the United States is hemoglobin S (HbS). Two genes for HbS result in sickle cell disease (SCD) or sickle cell anemia, which occurs in 0.3% of African Americans. One gene for HbS results in sickle cell trait, which occurs in 8% of African Americans. Hemoglobin C, another abnormality, occurs in 2% to 3% of African Americans. 

Sickle cell trait Sickle cell anemia Sickle cell hemoglobin C... 

Patients with sickle cell trait are usually asymptomatic, except for rare painless hematuria. 

It is also important to understand the source and significance of genetic variations. The Pima Indians have the highest rates of diabetes in the world Tay-Sachs disease is primarily found in Ashkenazi Jews. Contemporary literature indicates that these differences stem from reproductive isolation, not race. Genetic traits common to persons with sickle-cell disease are related to malaria frequency and not our social view of race. This is why the disease can be found in high frequency in Yemen, West Africa, Greece, and Saudi Arabia. 

Hypersensitivity to the drug conditions that might predispose patients to priapism (eg, sickle cell anemia or trait, multiple myeloma, leukemia) patients with anatomical deformation of the penis patients with penile implants (intracavernosal) use in women, children, or newborns use in men for whom sexual activity is inadvisable or contraindicated for sexual intercourse with a pregnant woman unless the couple uses a condom barrier. 

The answer is B. Sickle cell anemia is caused by inheriting two copies of a mutant P glo-bin gene that leads to synthesis of sickle hemoglobin, HbS. A severe case of sickle cell anemia would most likely have demonstrated symptoms and been diagnosed before the age of 6. However, he may only be a carrier, with one copy each of normal P-globin and one of the sickle allele, a condition called sickle cell trait. Nevertheless, the patient s... 

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