Hematological abnormalities in inborn errors of metabolism--how frequent are they? The Cretan experience

Inherited metabolic disorders in the neonatal intensive care unit: Red flags to look out for

BACKGROUND

We aimed to assess symptoms, laboratory findings, and radiological abnormalities in patients diagnosed with inherited metabolic disorders (IMDs) in the neonatal intensive care unit.

METHODS

A total of 6,150 newborns treated in a third-level neonatal intensive care unit between 2012 and 2020 in Turkey were screened, of which 195 consulted with a suspicion of metabolic disease based on their clinical, laboratory, or radiological findings were included in the present study.

RESULTS

The prevalence of IMDs in the patients was 1:94.6. Those consulted in the department of pediatric metabolism were divided into two groups, with the 65 diagnosed with IMDs assigned as Group I, and the 130 patients who were not diagnosed with IMDs as Group II. The most common IMDs were organic acidemias (29.23%) and urea cycle disorders (UCDs) (26.15%). The rates of consanguinity marriage (75.3% vs 37.6%, P < 0.001), siblings diagnosed with an IMD (27.6% vs 3.8%, P < 0.001), and sibling death (56.9% vs 14.6%, P < 0.001) were higher in Group I than in Group II. Hyperammonemia (61.5% vs 18.4%, P < 0.001) was the most common laboratory finding in Group I, and anemia (Group I 60.0% vs 43.0% P = 0.033), metabolic acidosis (53.8% vs 36.9%, P = 0.028) and respiratory alkalosis (16.9% vs 1.5%, P < 0.001) were all higher in Group I.

CONCLUSIONS

This retrospective study found that the results of clinical findings and basic laboratory tests could be strong indicators of IMDs, although extensive newborn screening tests and advanced biochemical and genetic tests should be carried out for the diagnosis of IMDs in newborns.

Hematologic Findings of Inherited Metabolic Disease: They are More Than Expected

Inherited metabolic diseases are pathologic conditions that generally develop as a result of impairment of the production or breakdown of protein, carbohydrate, and fatty acids. Early determination of hematological findings has a positive effect on the prognosis of metabolic diseases. Three hundred eighteen patients who were being followed-up within the previous 6 months at Department of Pediatric Nutrition and Metabolism, Gazi University, Turkey, were included in the study. The hematological findings were classified under 7 main groups: anemia of chronic disease, iron deficiency anemia, vitamin B12 deficiency anemia, hemophagocytosis, leukocytosis, and thrombocytosis. Nine hundred twenty-two hematological examinations of the 319 patients were included in the study, and 283 hematological findings were determined, 127 anemia of chronic disease, 81 iron deficiency anemia, 56 cytopenia, and 4 vitamin B12 deficiency anemia. Leukocytosis (n=1), thrombocytosis (n=5), and hemophagocytosis (n=9) were also observed. It was determined that, although anemia of chronic disease and nutritional anemia are the most common hematological findings, these may be diagnosed late, whereas neutropenia, thrombocytopenia, pancytopenia, and hemostasis disorders may be diagnosed earlier. Our study is the most comprehensive one in the literature, and we think it would positively contribute to the monitoring and prognosis of congenital metabolic diseases.

Haematological findings in children with inborn errors of metabolism

Early detection and therapy of haematological abnormalities and/or diseases may improve the prognosis of metabolic disorders. Accordingly, we aimed to evaluate the frequency and types of haematological abnormalities in children[-31pc] with various inherited metabolic disorders. The study group comprised 46 children with metabolic disorders who were followed at the Pediatric Metabolism Unit and were referred to the Pediatric Hematology Unit for evaluation of anaemia between June 2000 and 2005. The mean age of the children was 55.2 +/- 64.8 months at haematological evaluation (range 1 month-18 years, median 22.0 months); 16 were female and 30 were male. Of these 46 patients with anaemia, 25 of (54.3%) had anaemia of chronic disease (ACD), 9 (19.6%) had iron-deficiency anaemia (IDA), 7 (15.2%) had megaloblastic anaemia due to vitamin B(12) deficiency, 3 (6.5%) had chronic haemolytic anaemia, 2 (4.3%) had autoimmune haemolytic anaemia, 1 had beta-thalassaemia major, and 1 had hereditary spherocytosis. In addition to the anaemia, bicytopenia or pancytopenia was found in 8 of 46 children (17.4%). The study indicated that in organic acidaemias including methylmalonic acidaemia, propionic acidaemia, isovaleric acidaemia, and argininosuccinic acidaemia, the majority of patients had ACD (75%), which was followed by vitamin B(12) deficiency anaemia and IDA (p < 0.001). In PKU, both nutritional anaemias and ACD were present at about same frequency: 46.7% and 40%, respectively (p > 0.05). This study suggested that congenital anaemias such as hereditary spherocytosis or thalassaemias should be kept in mind as a coexisting haematological diseases in young patients with inborn errors of metabolism. In conclusion, ACD and nutritional anaemias are the most prevalent anaemias seen in patients with inborn errors of metabolism. Early detection of the disease, early administration of specific diet, and close monitoring of the patients are very important factors to prevent the development of haematological diseases in patients with inborn errors of metabolism.