Molecular and haematological characterisation of haemolytic anaemia associated with biallelic KLF1 mutations: a case series

AIMS

Krüppel-like factor 1 (KLF1) is an erythroid-specific transcription factor playing an important role in erythropoiesis and haemoglobin (Hb) switching. Biallelic KLF1 mutations can cause haemolytic anaemia with thalassaemia-like syndromes but are rarely reported. We explore the KLF1 mutations in Thai subjects with unexplainable haemolytic anaemia.

METHODS

The study was done on 57 subjects presented with haemolytic anaemia and elevated Hb F without β-thalassaemia diseases. Hb analysis was performed using capillary electrophoresis. Analyses of α-thalassaemia, β-thalassaemia and KLF1 genes were performed using PCR-based methods and DNA sequencing.

RESULTS

Thirteen subjects with compound heterozygous for a known and five new genetic KLF1 interactions were identified, including KLF1:c.519_525dupCGGCGCC/c.892G>C with class 3/2 (n=8), and each subject with new genetic interaction, including KLF1:c.-154C>T;643C>T/c.983G>A with class 3/2, KLF1:c.-154C>T;643C>T/c.809C>G with class 3/2, KLF1:c892G>C/c.983G>A with class 2/2, KLF1:c.892G>C/c.1001C>G with class 2/2 and KLF1:c.1001C>G/c.1003G>A with class 2/2. Most of them had anaemia with Hb levels ranging from 45 to 110 g/L, hypochromic microcytosis, aniso-poikilocytosis, increased Hb F levels (17.9%-47.4%), small amounts of Hb Bart's, regular blood transfusion, hyperbilirubinaemia, increased serum ferritin and nucleated red blood cell.

CONCLUSIONS

Biallelic KLF1 mutations associated with anaemia may not be uncommon in Thailand. Characteristics of haemolytic anaemia, abnormal red cell morphology with nucleated red blood cells and elevated Hb F, and presenting small amounts of Hb Bart's without thalassaemia diseases are useful markers to further investigation of the KLF1 gene.

Relapse of congenital thrombotic thrombocytopenic purpura, after spontaneous remission, in a second-trimester primigravida: case report and review of the literature

CONTEXT

Thrombotic microangiopathy syndrome or thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) describes distinct diseases sharing common pathological features: microangiopathic hemolytic anemia and thrombocytopenia, without any other apparent cause.

CASE REPORT

An 18-year-old second-trimester primigravida presented with a history of fifteen days of intense weakness, followed by diarrhea over the past six days. She reported having had low platelets since childhood, but said that she had never had bleeding or menstrual abnormalities. Laboratory investigation showed anemia with schistocytes, thrombocytopenia and hypohaptoglobulinemia. Red blood cell concentrate and platelet transfusions were performed. The hypothesis of TTP or HUS was put forward and ADAMTS13 enzyme activity was investigated. The patient evolved with increasing platelet counts, even without specific treatment, and she was discharged. One month afterwards, she returned presenting weakness and swollen face and legs, which had developed one day earlier. The ADAMTS13 activity was less than 5%, without presence of autoantibodies. Regarding the two previous admissions (at 9 and 16 years of age), with similar clinical features, there was spontaneous remission on the first occasion and, on the second, the diagnosis of TTP was suspected and plasmapheresis was performed, but ADAMTS13 activity was not investigated.

CONCLUSION

To date, this is the only report of congenital TTP with two spontaneous remissions in the literature This report reveals the importance of suspicion of this condition in the presence of microangiopathic hemolytic anemia and thrombocytopenia without any other apparent cause.

A patient with mixed type Evans syndrome: efficacy of rituximab treatment

Mixed type Evans syndrome is a very rare hematologic disease. Although mixed type Evans syndrome may initially respond well to steroids, this disease usually runs a chronic course with intermittent exacerbations. We describe here a 46-yr-old female with the steroid-refractory, mixed type Evans syndrome, and she had a prompt response to rituximab. She was diagnosed as having the mixed type Evans syndrome with the clinical features of symptomatic anemia, jaundice and thrombocytopenia. Prednisone therapy was commenced and her hemoglobin and platelet level returned to the normal. However, after 15 weeks, she relapsed with hemolytic anemia and thrombocytopenia. We started rituximab at the dose of 375 mg/m(2) once weekly for a total of 4 doses, which was well-tolerated and this induced the normalization of hemoglobin, bilirubin and lactic dehydrogenase, and there was also a significant increase of the platelet count.

Hemolytic anemia as a sequela of arsenic intoxication following long-term ingestion of traditional Chinese medicine

We report on a 51-yr-old woman who developed intravascular hemolytic anemia caused by arsenic after long-term ingestion of a traditional Chinese medicine (TCM). Twelve years before the admission, she was diagnosed as neurocysticercosis. She has ingested a TCM for about 12 yr instead of undergoing medical therapy for the disease. She was presented with a severe Coombs'-negative hemolytic anemia with hemosiderinuria. The urine arsenic level was elevated suggesting the arsenic intoxication as a cause of the anemia. She was treated successfully with therapeutic red cell exchange without any sequelae.