Molecular mechanisms underlying globin gene variants

Mechanisms	Examples
Single base substitution leading to amino acid replacement	Hemoglobin S
	Hemoglobin C
	Hemoglobin E
Two replacements in same subunit	Hemoglobin C-Harlem
Fusion hemoglobins	Hemoglobin Lepore (delta-beta)
	Hemoglobin Miyada (beta-delta)
	Hemoglobin Parchman (delta-beta-delta)
	Hemoglobin Kenya (gamma-beta)
Deletion or insertion	Hemoglobin Gun Hill
Insertion	Hemoglobin Grady
Insertion	Hemoglobin Catonsville
Deletion and insertion	Hemoglobin Montreal
Deletion and insertion	Hemoglobin Galicia
Extended subunit
Termination codon mutation	Hemoglobin Constant Spring
Frameshift mutation	Hemoglobin Wayne
Frameshift mutation	Hemoglobin Cranston
N-terminal mutation leading to retention of initiator methionine	Hemoglobin Long Island
	Hemoglobin Marseille

Refer to UpToDate for clinical information on these and other variants.

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