Ans. D: Fanconi's anemiaThe red cells in aplastic anemia are usually slightly macrocytic and normochromicFanconi anemia (rare autosomal recessive disorder caused by defects in a multiprotein complex that is required for DNA repair) underlie some forms of aplastic anemia.Conditions causing microcytic, hypochromic anemia in childhood includesIron deficiency,Beta-Thalassemia trait,Lead poisoning,Chronic illness or inflammation, andSideroblastic anemiaSideroblastic anemiaIt is characterized by:-- Ineffective erythropoiesis anemia with ringed sideroblasts,- Saturation of serum iron binding capacity (usually approaching 80%),- >LDH, and- Bizarre peripheral smear with hypochromia, distoed red cells, and basophilic stippling.Causes:- Hereditary or congenital: X-linked or autosomal recessive- Acquired sideroblastic anemiaIdiopathic refractory sideroblastic anemiaSecondary to: neoplasm (Di Guglielmo's disease erythroleukemia), inflammatory, hematologic, metabolic diseases.Associated with drugs or toxins: (1) Alcohol. (2) Lead. (3) Chloramphenicol. (4) Anti TB meds: INH. (5) Anti neoplastic alkylating agents as cytophosphamide.ThalassemiaInherited anemias characterized by defects in the synthesis of one or more globin chain subunits of the adult hemoglobin tetramer (Hb A).This leads to deficient hemoglobin accumulation, resulting in hypochromic and microcytic red cells and ineffective erythropoiesis and hemolytic anemia.Signs and symptoms: Thalassemia trait has no signs or symptoms.-- Pallor, Poor growth, Inadequate food intake, Fatigue, Shoness of breath, Splenomegaly, Jaundice, Maxillary hyperplasia, Dental malocclusion, Cholelithiasis, Pathologic fracturesLaboratory: In the presence of normal iron status, Increased levels of Hb A2 (to 4 to 6%) and/or increased Hb F (to 5 to 20%) by quantitative hemoglobin analysis suppos the diagnosis.Unfounately, differentiation between iron deficiency anemia and beta- or alpha-thalassemia trait can be difficult in practice if no reciprocal increases in Hb A2 levels and/or Hb F are present.- The distinction between alpha- and beta-thalassemia depends on the measurement of the minor hemoglobins Hgb A2 and Hgb F.- If these are normal, the diagnosis of alpha-thalassemia is most likely.Hemoglobin electrophoresis:- Elevated Hb A2 levels in beta-thalassemia trait- Elevated Hb A2, elevated Hb F, reduced or absent Hb Al in beta-thalassemia major or intermedia Peripheral blood:- Pronounced microcytosis,- Anisocytosis,- Poikilocytosis,- Hypochromia,- Punctate basophilic stippling,- High percentage of target cells, nucleated RBC,- Reticulocyte count elevatedHematocrit:- 28-40% in alpha-thalassemia trait and beta-thalassemia trait- May fall to less than 10% in beta-thalassemia majorFanconi anemia (FA)It is a genetic disease with an incidence of 1 per 350,000 bihsFA is the result of a genetic defect in a cluster of proteins responsible for DNA repair.As a result, the majority of FA patients develop cancer, most often acute myelogenous leukemia, and 90% develop bone marrow failure by age 40.Clinically, hematological abnormalities are the most serious symptoms in FA.While at bih, blood count is usually normal, macrocytosis/megaloblastic anemia is the first detected abnormality, often within the first decade of life (median age of onset is 7 years).Within the next 10 years, over 50% of patients presenting haematological abnormalities will have developed pancytopenia.Most commonly, a low platelet count (thrombocytopenia) precedes a low neutrophil count (neutropenia)