Heterozygotes present with mild clinical picture with fully compensated hemolysis whereas homozygotes and compound heterozygotes
like hereditary elliptocytosis in combination with beta thalassaemia trait present with severe hemolytic anaemia due to mutual enhancement of involved genes4.
The effect of hydroxyurea on compound heterozygotes
for sickle cell-hemoglobin D-Punjab--a single centre experience in eastern India.
The genetic pathogenesis mainly involves three different gene alterations; they can be homozygotes, compound heterozygotes
or double heterozygotes.
Apart from the rare dominant forms, subjects with thalassemia major are homozygotes or compound heterozygotes
for beta0 or [beta.
One of the most persistent problems in clinical genetic testing is interpretation of compound heterozygotes
PATHOPHYSIOLOGY OF COMPOUND HETEROZYGOTES
INVOLVING HEMOGLOBINOPATHIES AND THALASSEMIAS
Heterozygotes for C282Y, the homozygosity for variant H63D, and the compound heterozygotes
of H63D and C282Y also succumb to hemochromatosis with a lower penetrance (Burke et al.
It is also demonstrated that these SE alleles show a dose effect with homozygotic individuals carrying increased risk over heterozygotes and some compound heterozygotes
reveal a greater risk indeed, for example, the heterozygous combination of DRB1*0401/*0404 is identified to be strongly associated with early onset and a more severe form of disease than homozygosity for either allele (13, 14).
For C282Y homozygotes or compound heterozygotes
diagnosed under the age of 40 years and with no biochemical or clinical evidence of liver disease, phlebotomy therapy (described later) can be initiated without the need for liver biopsy.
Individuals who are compound heterozygotes
for a pseudodeficiency allele and a true TSD mutation would appear to be affected using HexA testing, thereby explaining the unaffected adults with HexA deficiency results.
Low DN values normally indicate the A phenotype (DN typically 20-30), which is demonstrated only by homozygotes for the defining Asp70Gly mutation (A/A genotype) or by its compound heterozygotes
with a silent variant mutation (A/S genotype)--the silent variant gene product contributing little to the total.
8,9) The De Caluwe manuscript described 19 AC heterozygotes and 5 SC compound heterozygotes
in which Haitian subjects were the least represented and no prevalence data was reported.