Question

Salina is a 7-year-old who lives with her parents in a suburban community. Her parents brought Salina to the United States from their homeland in Greece when she was 1 year old. At the age of 3, Salina was in the 10th percentile for height and weight, pale, and her hemoglobin was 5.8 g/dL. Following further diagnostic studies, she was diagnosed with beta-thalassemia major. Over the course of the next 4 years, Salina was hospitalized every 1–2 months so she could be transfused with packed red blood cells.

During a routine follow-up visit at the hematology clinic,Salina’s laboratory results were as follows: Hemoglobin: 10 mg/dL Total serum iron: 150 mcg/dL.

1.)What is Beta-Thalassemia. Discuss the incidence, and etiology and the significance of Salina's family's geographic background to her diagnosis.

Answer 1

1. Beta Thalassemia is a blood disorder that reduces the production of haemoglobin A. Low levels of haemoglobin results in insufficient supply of blood to different part of the body. Haemoglobin can bind to oxygen and carbon dioxide and is an important carrier of oxygen and carbon dioxide. Shortage of oxygen supply leads to fatigue, weakness, pale skin, and increased risk of developing blood clots. Beta thalassemia can be thalassemia major (Cooney’s disease), thalassemia minor and thalassemia intermedia, a milder form.

Incidence of beta thalassemia: Incidence of this disease is 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Around 1.5% of global populations are carriers of beta thalassemia. Highest incidence rates are observed in Cyprus (14%), Sardinia (10.3%), and Southeast Asia. The Thalassemia International Federation estimates that about 200,000 patients with thalassemia major are alive and receiving treatment around the world. Around 60,000 symptomatic individuals are born every year.

Etiology: Haemoglobin is a tetramer of two alpha and two beta subunits. The beta globin genes are located on Chromosome 11. Point mutations or rarely deletions in beta globin genes lead to beta thalassemia. These mutations lead to effects on initiation or termination of transcription, abnormal RNA splicing or cleavage, and substitutions. Total loss of Hb beta is due to nonsense, frame shift, or splicing mutations. Co-inheritance of alpha gene mutations and persistence of fetal Hb can result in milder syndrome due to restoration of globin balance. In beta thalassemia major, both copies/ alleles of the gene is mutated. It can be inherited if both parents are carriers.

Thalassemia major leads to severe hemolytic anemia in children, who require frequent blood transfusions. Blood transfusions lead to iron overload. It is known as Mediterranean anemia as its more frequent in people of Greek and Italian origin. These regions had more incidence of malaria. The gene thrived in this population as thalassemia minor provided protection against malaria. Symptoms of thalassemia major appear in children in first year of life when fetal Haemoglobin (Hb) is replaced by adult Hb A, the predominant form of Hb. These children have pale skin, irritability, growth retardation, enlargement of the liver and spleen with jaundice.

Salina is one year old child and has a Greek origin, which is the reason that she carries the aberrant gene. She must have inherited the gene from her parents. Her iron content is high (normal levels in child: 50-120 mcg/dL) due to frequent blood transfusion. Hb content in 6-12 yr child should be 11.5-15.5 g/dL. Salina has a much-reduced Hb content.