In cooperation with paediatric haematologists from the Czech Republic, the Diamond-Blackfan anaemia (DBA) registry was created. Twenty six patients with chronic hypoplastic anaemia were investigated. Twenty two patients met the diagnostic criteria for DBA. The incidence of DBA in our country estimated from our registry is 7 DBA cases per million live births. The other 4 patients suffered from chronic parvovirus B 19 infection (2), Fanconi anaemia (1), transient erythroblastopenia (1). In the group of DBA patients are 11 boys and 11 girls, the age range is 4 months to 20 years. There are 3 families with more than one case of DBA in the registry, two families with autosomal dominant and one with an autosomal recessive inheritance. Diagnosis of DBA was established during first 10 months of life in all cases. Eleven patients (50%) were anaemic already in neonatal age. Four patients (18 %) with hypotrophy at births and 4 (18 %) premature births (35th - 37th week of pregnancy) were identified. The average birth weight of boys was significantly lower than of mature healthy newborn boys (p < 0.0078). An increased frequency of miscarriages in DBA families was not confirmed. In 10 (46 %) patients we described physical anomalies, in five children hypoplasia of the thenar, in one of these children with a bifid distal phalanx, in 2 cases a ventricular septal defect, in one patient renal aplasia and in four craniofacial dysmorphism. The height of 12 (55%) children is below the 3rd percentile for age. Only 3 patients have neither associated anomalies nor a short stature. MCV was increased in 15 (68%) of patients. The HbF level was increased in 14/19 patients (74%), and i antigen expression was found in 13/19 (67%) patients. The erytropoetin level was elevated in all patients. Adenosine deaminase (ADA) activity levels were normal in all transfusion-dependent patients and raised in 94% of patients in the steroid-dependent group. In two families elevated ADA activity levels in three healthy non-ana- emic individuals were found. Thirteen patients (55%) are treated with corticosteroids, 4 patients (18%) are transfusion dependent, 4 (18%) patients are in remission. Two patients had a favourable outcome after allogenic BMT from a HLA identical sibling. One girl died after BMT due to the acute form of GVHD. One patient from the transfusion-dependent group died of a severe iron overload with dilatation cardiomyopathy. In 3 children the authors found by the PCR method chronic infection caused by Parvovirus B 19 with substantial deterioration of the clinical picture of the disease in one of them. In all patients in vitro cultivation of progenitor cells and molecular-genetic analysis of possible ribosomal protein RPS 19 mutations will be made. The DBA registry will be included in the European DBA registry for further research of the etiology and pathogenesis of this rare disorder.

        Key words: Diamond-Blackfan anaemia, growth factors, associated anomalies, adenosine deaminase, parvovi-