Haemoglobinopathies and Sickle Cell Disease

These flashcards cover key terms and definitions related to Haemoglobinopathies and Sickle Cell Disease, drawn from the lecture notes to assist in exam preparation.

Haemoglobin

A protein in red blood cells that carries oxygen.

HbA

Normal adult hemoglobin, comprising 96-98% of adult hemoglobin.

HbF

Fetal hemoglobin, comprising 0.5-0.8% in adult blood.

HbA2

A minor component of adult hemoglobin, comprising 1.5-3.0%.

Haemoglobin S (HbS)

An abnormal hemoglobin resulting from a point mutation in the beta-globin gene.

Haemoglobin C

An abnormal hemoglobin where lysine replaces glutamic acid at position 6.

Haemoglobin E

An abnormal hemoglobin commonly found in Southeast Asia.

Haemoglobin D

An abnormal hemoglobin variant that shares electrophoretic mobility with HbS and HbKB.

Mutation

A change in the DNA sequence that can lead to abnormal hemoglobin.

Sickle Cell Trait

A condition where an individual carries one sickle cell gene and one normal gene.

Homozygous

Having two identical alleles for a particular gene.

Heterozygous

Having two different alleles for a particular gene.

Polymerization

The process where deoxygenated HbS molecules aggregate to form rigid structures.

Hypoxia

A condition in which there is insufficient oxygen in the tissues.

Splenomegaly

Enlargement of the spleen often associated with conditions like Sickle Cell Disease.

Target cells

Red blood cells that have a bull's-eye appearance, often found in hemoglobin disorders.

Vaso-occlusive crises

Painful episodes resulting from blocked blood flow due to sickled red blood cells.

Acidosis

A condition in which there is an excess of acid in the blood, leading to lower pH.

Blood transfusion

The process of transferring blood or blood components into a patient's circulation.

Folic acid

A vitamin used to help increase red blood cell production and prevent anemia.

Hydroxyurea

A medication that stimulates the production of fetal hemoglobin (HbF).

Gene therapy

A technique that modifies a person's genes to treat or prevent disease.

Thrombosis

The formation of a blood clot in a blood vessel, often leading to complications.

Chronic haemolytic anaemia

A persistent reduction in hemoglobin due to the destruction of red blood cells.

Electrophoresis

A laboratory technique used to separate proteins based on their size and charge.

Sickle Cell Disease (SCD)

A genetic disorder characterized by the presence of sickle-shaped red blood cells.

Retinopathy

Damage to the retina due to various causes, including sickle cell disease.

Dactylitis

Painful swelling of the fingers or toes, often seen in children with SCD.

Renal dysfunction

Impaired kidney function, which can occur in individuals with SCD.

Gallstones

Solid particles that form in the gallbladder, often due to increased bilirubin.

Sequestration crisis

A sudden trapping of red blood cells in the spleen, leading to severe anemia.

Infarction

Tissue death due to a lack of blood supply, common in VOCs of SCD.

Bone marrow hyperplasia

Increased production of blood cells in the bone marrow, often seen in chronic anemia.

Pain management

Strategies and treatments employed to relieve pain, especially in SCD crises.

Sodium dithionite test

A screening test used to detect sickling in red blood cells.

Asplenia

Absence of normal spleen function, increasing infection risk in SCD patients.

Hydration

The process of providing adequate fluids, crucial for preventing sickling crises.

Microvascular changes

Alterations in small blood vessels that can lead to complications in SCD.

Electrophoretic mobility

The rate at which molecules move through a medium when an electric current is applied.

Laboratory diagnosis

Testing and examination procedures to identify diseases.

Gene editing

A molecular technique used to change an organism's DNA, including CRISPR technology.

Under-expressed allele

An allele that is not expressed as dominantly as another.

Painful crises

Episodes of severe pain experienced by individuals with SCD due to vaso-occlusion.

Life expectancy

The average period that a person may expect to live, often affected by SCD.

Genetic counseling

Guidance provided to individuals regarding genetic disorders and inheritance.

Infections

Diseases caused by pathogens, which are a risk for patients with SCD due to splenic dysfunction.

Severe hypoxia

A critical lack of oxygen in the body, often triggering sickle cell crises.

Bacteriuria

The presence of bacteria in urine, which can lead to urinary tract infections.

Pyelonephritis

Kidney infection that can occur in SCD patients due to urinary complications.

Clinical features

Observable characteristics and symptoms of a disease.

Electrophoretic variants

Different forms of hemoglobin that can be separated by electrophoresis.

Transfusion reactions

Adverse responses by the body to transfused blood or blood products.