History and exam
Key diagnostic factors
Other diagnostic factors
common
childhood or young adulthood
Because alpha-thalassemia can have such wide variability in clinical manifestations, patients may present anywhere from in utero, with hydrops fetalis, to any point during adulthood, with an asymptomatic microcytosis. However, those with more severe manifestations will generally present in childhood or young adulthood.
family history of alpha-thalassemia
Known family history of alpha-thalassemia will facilitate making the diagnosis.
symptoms of gallstones
Symptoms of bloating, abdominal pain, and gas are suggestive of gallstones, which are fairly common in Hb H disease.
uncommon
history of prior iron supplementation
Iron supplementation may have been given unnecessarily in the past for a microcytic anemia.
jaundice
mild dysmorphic facial features
Risk factors
strong
ethnicity from a geographic malarial area
Alpha-thalassemia is common in sub-Saharan Africa, the Mediterranean basin, the Middle East, South Asia, and Southeast Asia; different genetic subtypes have variable frequencies in each of these areas.[19][20][21]
Alpha(0) variants, which can lead to hemoglobin H (Hb H) disease or alpha-thalassemia major, are most common in Southeast Asia, southern China, and the Mediterranean; prevalence of carriers is 14% in northern Thailand and 5% to 8.8% in southern China.[11]
positive family history
Alpha-thalassemia is a common inherited blood disorder; approximately 5% of the global population carry a defective alpha-thalassemia gene.[16][17]
The apparent lack of family history does not preclude the presence of alpha-thalassemia in a newborn. Parents with a mild or even silent clinical phenotype may give rise to offspring with a more severe phenotype (i.e., if both parents are heterozygous for the (--SEA) deletion they have a 25% chance of conceiving a child who has the almost universally fatal homozygous (-- SEA/--SEA) genotype).
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