RESUMO
UNLABELLED: We report on the fatal clinical course of a 3 year old male Turkish patient suffering from osteopetrosis caused by a homozygous mutation in the chloride channel gene ClCN7 with developing pancytopenia and severe neurological impairment. Hepatosplenomegaly due to extramedullary hematopoesis, severe transfusion-dependent anemia and growth failure initially suggested metabolic or oncologic disorder. Particular haematological parameters like tear drop cells basophilic punctation of the polymorphonuclear cells in the absence of haemolysis caused the diagnostic X-ray investigations of the skull and vertebral column. Raised serum creatinkinase-BB isoenzyme and genetic testing were in line with the diagnose of osteopetrosis at an age of 2(1/2) years. CONCLUSION: Osteopetrosis is a rare but considerable differential diagnose for unclarified change in haematopoetic cell lines combined with severe neurological symptoms mimicking metabolic or haematological disease. Because of this rare disease a consensus protocol for diagnostics, treatment and follow up of patients suffering from osteopetrosis is recently worked out from the European Group of Blood and Marrow Transplantation (EBMT) and the European Society for Immundeficiencies (ESID) to build up a central registry for this disease (available by ansgar.schulz@uniklinik-ulm.de).
Assuntos
Canais de Cloreto/genética , Análise Mutacional de DNA , Hematopoese Extramedular/genética , Homozigoto , Doenças Neurodegenerativas/genética , Osteopetrose/genética , Fosfatase Alcalina/sangue , Pré-Escolar , Aberrações Cromossômicas , Códon/genética , Creatina Quinase Forma BB/sangue , Diagnóstico Diferencial , Epilepsia/diagnóstico por imagem , Epilepsia/genética , Éxons/genética , Evolução Fatal , Genes Recessivos/genética , Humanos , Masculino , Doenças Neurodegenerativas/diagnóstico por imagem , Osteopetrose/diagnóstico por imagem , Radiografia , Crânio/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagemRESUMO
BACKGROUND: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients. OBJECTIVE: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients. METHODS: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors. RESULTS AND CONCLUSIONS: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.
