Families and Thalassemia Mariam Alosfoor

Case study

Eight years later, she tells you that she is happily married with a Saudi person from Hofuf.

They decided to start a family. Remarkably, several family members of her husband living in the city need regular blood transfusions.

She wonders whether her children might have an increased risk of genetic disorder causing anemia.

Objectives

Hemoglobin Types

Thalassemia

Genetics of Thalassemia

What is your advise to this patient and her husband?

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Hemoglobin types

HbA α2β2 Normal

HbF α2γ2 Fetal

HbH β4 α thalassemia

HbA2 α2δ2 β thalassemia

Hb Barts γ4 α thalassemia

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Thalassemia

Defects in production of the α or β chains of hemoglobin

Resulting imbalance in globin chains leads to hemolysis in the spleen or bone marrow

Increase severity with increasing number of alleles involved

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Microcytic Anemia

Hb Heme

Fe++

Iron deficiency anemia

Anemia of chronic disease

Protoporphyrin

Sideroblastic anemia

Globin

α chain

α thalassemia

β chain

β thalassemia

= +

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Genetics of Thalassemia

4 α genes in total; 2 on each copy of chromosome 16

2 β genes in total; 1 on each copy of chromosome 11

Hb types Thalassemia

Genetics of

Thalassemia

Advice Lab work Genetic Counseling

Thalassemia

α thalassemia

1 gene

Asymptomatic

2 genes

Mild anemia

3 genes

Severe anemia

4 genes

Lethal

β thalassemia

Minor(β/β+)

Asymptomatic

Major(β0/β0)

Severe anemia

Advice

Confirm parents blood condition Lab work Genetic testing

Genetic Counseling

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Lab work

Complete Blood Count (CBC) Hb, MCV, Fe, RBC

count

Microscopy

Hb electrophoresis

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work Genetic

Counseling

Thalassemia

A thalassemia

1 gene

Asymptomatic

HbA

2 genes

Mild anemia

HbA

3 genes

Severe anemia

HbH

4 genes

Lethal

Hb Barts

B thalassemia

minor

Asymptomatic

HbA

major

Severe anemia

HbF

Hb Electrophoresis

Genetic Counseling

Communication process of providing information and support to individuals and families with a diagnosis and/or risk of occurrence of an inherited disorder.

Genetic counseling is needed: at diagnosis and during adolescence prior to and after any genetic testing prior to pregnancy and/or as early in pregnancy as possible Annual follow-ups are needed to reinforce teaching.

Hb types Thalassemia

Genetics of Thalassemi

aAdvice Lab work

Genetic Counselin

g

Genetic Counselin

g

.

.

.

.

.

Summary

What have we been talking about?

References

St. Jude Children’s Research Hospital, article

Cooley’s Anemia Foundation, article

Northern California Comprehensive Thalassemia Center, article

Torronto notes 2012

Pathoma notes