Familial dysalbuminemic

Unfortunately, FT4 and FTa estimate methods have been found to be unreHable in a number of situations. One of these is familial dysalbuminemic hyperthyroidism, an inherited disorder in which a normally minor component of serum albumin is increased. This variant albumin binds T4 with abnormally high affinity, but its avidity for T3 is not comparably increased. Although total T4 concentrations are usually high, patients with familial dysalbuminemic hyperthyroidism are clinically euthyroid, and free hormone concentrations are normal as measured by reference methods... 

The function of most albumin isoforms is normal, although some have abnormal binding affinities for thyroxine (T4). Binding may be increased, as in familial dysalbu-minemic hyperthyroxinemia, or decreased. Individuals with famihal dysalbuminemic hyperthyroxinemia are euthyroid but have elevated serum T4 and free T4 index the variant albumin comigrates with Alb A. Two glycosylated variants. Alb RedhiU and Alb Casebrook, have altered fatty acid binding properties. 

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