Although only the erythrocyte shows pathological effects of this disorder, UMPH 1 is selectively deficient in patients' mononuclear and lymphoblastoid cells and accumulation of slightly raised levels of UTP and UDP sugars has also been noted. The age of presentation has varied widely. Other characteristic findings include reticulocytosis, anisocytosis, splenomegaly and sometimes cholelithiasis. In addition, two recent cases showed intravascular haemolysis, haemoglobulinuria, urinary iron loss and enlarged kidneys. Biopsy showed iron in the epithelium of the proximal tubules.
Heterozygotes are clinically and haematologically normal.
This is an autosomal recessive disorder. The defect has been reported in a number of families, affecting both children and adults, showing a wide distribution around the world. Individuals of Jewish or African ancestry may be particularly susceptible. Heterozygotes may be difficult to detect. Electrophoretic analysis of erythrocytes, lymphocytes and lymphoblasts from patients with the disorder have shown a complete deficiency of the major isoenzyme UMPH 1.