Mutations in the Drosophila mitochondrial tRNA amidotransferase, bene/gatA, cause growth defects in mitotic and endoreplicating tissues.

Rapid larval growth is essential in the development of most metazoans. In this article, we show that bene, a gene previously identified on the basis of its oogenesis defects, is also required for larval growth and viability. We show that all bene alleles disrupt gatA, which encodes the Drosophila homolog of glutamyl-tRNA(Gln) amidotransferase subunit A (GatA). bene alleles are now referred to as gatA. GatA proteins are highly conserved throughout eukaryotes and many prokaryotes. These enzymes are required for proper translation of the proteins encoded by the mitochondrial genome and by many eubacterial genomes. Mitotic and endoreplicating tissues in Drosophila gatA loss-of-function mutants grow slowly and never achieve wild-type size, and gatA larvae die before pupariation. gatA mutant eye clones exhibit growth and differentiation defects, indicating that gatA expression is required cell autonomously for normal growth. The gatA gene is widely expressed in mitotic and endoreplicating tissues.

Light chain Fanconi syndrome in a patient with acute myeloid leukemia and monoclonal gammopathy of undetermined significance.

Proximal tubules are a target for paraproteinemic diseases. Cast nephropathy, light chain deposition diseases, and amyloidosis are frequently encountered in patients with multiple myeloma. Rarely, a subset of patients develop light chain Fanconi syndrome (LCFS). LCFS has been reported with multiple myeloma, monoclonal gammopathy of renal significance (MGRS), chronic lymphocytic leukemia, Waldenstrom's macroglobulinemia and diffuse large B-cell lymphoma. No cases have been described with other hematologic malignancies. We report the first case of lambda LCFS in a patient with both acute myeloid leukemia (AML) and monoclonal gammopathy of undetermined significance (MGUS).