SIFD as a novel cause of severe fetal hydrops and neonatal anaemia with iron loading and marked extramedullary haemopoiesis

SIFD describes a heritable, syndromic condition characterised principally by sideroblastic anaemia (SA) with immunodeficiency, fevers and developmental delay, arising in mutations within the TRNT1 gene. Other clinical manifestations of SIFD include cardiomyopathy, seizures, sensorineural hearing loss, renal dysfunction, metabolic abnormalities, hepatosplenomegaly and retinitis pigmentosa.

Presentation of SIFD is variable but typically in early childhood with SA or with fever. In this report, we extend the described SIFD phenotype. We describe a kindred in which the index case presented with fetal hydrops, and early neonatal death, and the second child had severe anaemia at delivery. Both cases had prominent extramedullary erythropoiesis and numerous circulating nucleated red blood cells.

Recent advances in the understanding of myelodysplastic syndromes with ring sideroblasts

Myeloid neoplasms with ring sideroblasts are currently categorized within the myelodysplastic syndromes (MDS) or myelodysplastic/myeloproliferative neoplasms (MDS/MPN) in the World Health Organization classification. Recent findings have identified that the presence of ring sideroblasts in these disorders has a unique molecular basis, i.e., the somatic mutation of SF3B1, a gene encoding a splicing factor. Mutations of SF3B1 occur in up to 90% of patients with refractory anaemia with unilineage dysplasia (RARS) and 70% of those with refractory cytopenia with multilineage dysplasia and ring sideroblasts or RARS associated with marked thrombocytosis. Experimental evidence has shown that mutant SF3B1 results in the abnormal splicing of several genes, primarily due to misrecognition of 3' splice sites. The resulting aberrant mRNAs undergo nonsense-mediated mRNA decay (NMD), resulting in haploinsufficiency of canonical transcripts and protein expression. In addition, it is also possible that NMD-insensitive aberrant transcripts are translated into proteins with altered function. Patients with MDS carrying the SF3B1 mutation show a homogeneous disease phenotype characterized by isolated erythroid dysplasia and mild dysplasia in granulocytic or megakaryocytic lineages, supporting the notion that the SF3B1 mutation identifies a distinct entity within MDS. The available evidence suggests that these findings may have relevant impact on the diagnosis, classification and management of patients with these neoplasms.

Severe isoniazid related sideroblastic anemia

Isoniazid induced sideroblastic anemia is a rare event. We report case of a 45 year old Caucasian women with development of severe anaemia 4 month after introduction of Isoniazid as part of Tuberculosis treatment. While haemoglobin fell to 47 g/L and erythrocyte count to 1.5 G/L, reticulocytes were very low (reticulocyte production index of 0.48), but bone marrow aspirate showed an accelerated erythropoiesis with ringsideroblasts. Anaemia rapidly resolved after cessation of Isoniazid. We postulate an Isoniazid induced inhibition of the δ-Amino-levulinat-synthase resulting in marked depletion of heam synthesis.