Hemoglobin Portland 1: a new human hemoglobin unique in structure.

A new hemoglobin (Hb), Portland 1, has been found in a newborn infant having multiple congenital anomalies and complex autosomal chromosomal mosaicism. The new hemoglobin has a unique tetrameric structure (molecular weight, 66,000) composed of two pairs of different types of chains, neither of which is alpha, gamma(2)x(2). The x-chain of Hb Portland 1 may be a new type of hemoglobin chain, but the available evidence suggests that it may be identical with the epsilon chain. We suggest that Hb Portland 1 is an embryonic hemoglobin that persisted until after birth in relatively large amounts in this patient.