Which anemia is associated with absent radii and thumbs, hyperpigmentation, and microcephaly?

Fanconi's anemia is a specific type of inherited bone marrow failure that is associated with a variety of congenital anomalies, including absent radii and thumbs, hyperpigmentation, and microcephaly. This form of anemia results from defects in DNA repair mechanisms, leading to a predisposition to aplastic anemia and certain malignancies.

Individuals with Fanconi's anemia often exhibit physical deformities that include upper limb malformations (such as absent radii and/or thumbs), various skin pigmentation abnormalities, and reduced head size (microcephaly). These manifestations are due to the genetic mutations that affect developing tissues from early embryonic development.

The presence of these distinctive clinical features, along with the hematological findings such as pancytopenia, makes Fanconi's anemia a unique condition in the differential diagnosis of anemias and congenital conditions.