Summary: The thalassemias can be defined as α‐ or β‐thalassemias depending on the defective globin chain and on the underlying molecular defects. The recognition of carriers is possible by hematological tests. Both α‐ and β‐thalassemia carriers (heterozygotes) present with microcytic hypochromic parameters with or without mild anemia. Red cell indices and morphology followed by separation and measurement of Hb fractions are the basis for identification of carriers. In addition, iron status should be ascertained by ferritin or zinc protoporphyrin measurements and the iron/total iron‐binding capacity/saturation index. Mean corpuscular volume and mean corpuscular hemoglobin are markedly reduced (mean corpuscular volume: 60–70 fl; MCH: 19–23 pg) in β‐thalassemia carriers, whereas a slight to relevant reduction is usually observed in α‐carriers. HbA₂ determination is the most decisive test for β‐carrier detection although it can be disturbed by the presence of δ‐thalassemia defects. In α‐thalassemia, HbA₂ can be lower than normal and it assumes significant value when iron deficiency is excluded. Several algorithms have been introduced to discriminate from thalassemia carriers and subjects with iron‐deficient anemia; because the only discriminating parameter is the red cell counts, these formulas must be used consciously. Molecular analysis is not required to confirm the diagnosis of β‐carrier, but it is necessary to confirm the α‐thalassemia carrier status. The molecular diagnosis is essential to predict severe transfusion‐dependent and intermediate‐to‐mild non‐transfusion‐dependent cases. DNA analysis on chorionic villi is the approach for prenatal diagnosis and the methods are the same used for mutations detection, according to the laboratory facilities and expertise.

Porphyrias are a group of diseases that are clinically and genetically heterogeneous and originate mostly from inherited dysfunctions of specific enzymes involved in heme biosynthesis. Such dysfunctions result in the excessive production and excretion of the intermediates of the heme biosynthesis pathway in the blood, urine, or feces, and these intermediates are responsible for specific clinical presentations. Porphyrias continue to be underdiagnosed, although laboratory diagnosis based on the measurement of metabolites could be utilized to support clinical suspicion in all symptomatic patients. Moreover, the measurement of enzymatic activities along with a molecular analysis may confirm the diagnosis and are, therefore, crucial for identifying pre-symptomatic carriers. The present review provides an overview of the laboratory assays used most commonly for establishing the diagnosis of porphyria. This would assist the clinicians in prescribing appropriate diagnostic testing and interpreting the testing results.

Porphyria refers to a group of fascinating diseases from a metabolic and nutritional standpoint as it provides an example of how metabolic manipulation can be used for therapeutic purposes. It is characterized by defects in heme synthesis, particularly in the erythrocytes and liver. Specific enzymes involved in heme biosynthesis directly depend on adequate levels of vitamins and minerals in the tissues. Moreover, micronutrients that are required for producing succinyl CoA and other intermediates in the Krebs (TCA) cycle are indirectly necessary for heme metabolism. This review summarizes articles that describe the nutritional status, supplements intake, and dietary practices of patients affected by porphyria, paying special attention to the therapeutic use of nutrients that may help or hinder this group of diseases.