Myeloid, erythroid, and immune system defects in a family. A new stem-cell disorder?

Four of six siblings, offspring of Sicillian first cousins, developed a clinical disorder in early adulthood affecting the hematopoietic and immunoglobulin-producing systems. A female sibling died at age 21 with myeloid aplasia and agranulocytosis. A male sibling, at age 17, presented with erythroid and plasma cell aplasia with hypogammaglobulinemia. Two other female siblings, ages 21 and 35, had a lymphoproliferative disorder associated with hypogammaglobulinemia. In two of the affected subjects there was complete absence of the enzyme leukocyte alkaline phosphatase. Electron microscopic studies of the peripheral leukocytes from these two subjects and from one of the two asymptomatic siblings showed curious intranuclear and intracytoplasmic linear "crystalloid" structures in the mature neutrophils. It is postulated that the family contains a genetic defect, transmitted as an autosomal recessive by the heterozygous parents, that produces a stem-cell disorder manifested by myeloid, erythroid, and plasma cell aplasias, unique electron microscopic findings, and morphologic and functional abnormalities in later generations of cells.