Hema lec- midterm dna anomalies

Megaloblastic anemia

What is the hallmark of DNA metabolism disorders characterized by very large bone marrow precursor cells?

Megaloblasts

What are the very large bone marrow precursor cells in megaloblastic anemia called?

Larger erythrocyte precursors with relatively immature nuclei, finely reticulated chromatin, and abundant basophilic cytoplasm.

What are the characteristics of megaloblasts?

Transfers single-carbon units (methyl groups) from donors to receptors; essential for cell replication.

What is the physiologic role of folate?

Prevents the methylation of dUMP to dTMP, impairing DNA synthesis.

What biochemical defect occurs in folate deficiency?

Cofactor in converting 5-methyl THF to THF and homocysteine to methionine, and methylmalonyl-CoA to succinyl-CoA.

What is the physiologic role of vitamin B12?

Prevents production of THF from 5-methyl THF, trapping folate in the methyl-THF form.

What biochemical defect occurs in vitamin B12 deficiency?

Required for the conversion of homocysteine to methionine.

What is the function of methyl-B12?

Required for the conversion of methylmalonyl-CoA to succinyl-CoA.

What is the function of adenosyl-B12?

Neural tube defects (e.g., spina bifida) and cardiovascular disease.

What specific manifestations are associated with folate deficiency?

Neurological symptoms, in addition to general anemia and GI tract issues.

What specific manifestations are associated with vitamin B12 deficiency?

Glossitis, gastritis, nausea, and constipation.

What are the alimentary tract symptoms of megaloblastic anemia?

Fatigue, weakness, and shortness of breath.

What are the general symptoms of anemia?

Inadequate intake, increased need, impaired absorption, impaired utilization, and excessive loss.

What are the causes of folate deficiency?

Inadequate intake, increased need, failure to separate from food/haptocorrin, lack of Intrinsic Factor (IF), inherited errors of transport/absorption, malabsorption, and competition.

What are the causes of vitamin B12 deficiency?

Myelodysplastic Syndrome (MDS), Congenital Dyserythropoietic Anemia (CDA), Acute Erythroleukemia, and Reverse Transcriptase Inhibitors.

What are the non-megaloblastic causes of megaloblastosis?

Oval macrocytes (megalocytes) and hypersegmented neutrophils.

What are the peripheral blood findings in megaloblastic anemia?