What are the symptoms? Some children with DBA may show physical features such as an extra thumb joint, cleft palate (see entry Cleft Lip and/or Palate) and or a characteristic facial appearance. Many affected children are very short for their age, and may have delayed puberty. Children with DBA otherwise develop normally, and it is unusual for affected children to have learning difficulties. What are the causes? The anaemia is caused by a failure of the bone marrow to produce red blood cells (‘red cell aplasia’). The exact cause is not clear, but the problem seems to be a fault in one of the early steps of red blood cell production. In up to 25 per cent of affected children there is a fault within a gene called small ribosomal protein 19, or RPS19. Mutations in other parts of the genes which code for ribosomes have more recently been discovered in a further 25 per cent of cases. Ribosomes are very important in helping the cell to function properly. These mutations interfere with the working of the cell, stopping the red cells from being produced. Infection with a particular virus (parvovirus) can cause a switch off of red blood cell production. Nearly always this lasts for such a short time that it goes unnoticed, but infection during pregnancy can sometimes cause severe anaemia in the baby. There is also a condition known as ‘transient erythroblastopenia of childhood’ in which red cell production is temporarily switched off, usually following a viral infection. This is rare in babies, being most common in toddlers and pre-school children. This gets better on its own within a few months, and can sometimes be difficult to tell apart from DBA, except by waiting to see if the anaemia improves on its own. How is it diagnosed? The diagnosis is easy if there is already an affected child within the family, or the baby has a physical feature of DBA. Otherwise, it is a matter of confirming that the problem lies in a red blood cell production failure, and then to exclude parvovirus infection. Preliminary blood tests will show if too few red blood cells are being produced. The next step is for a small sample of bone marrow to be taken, to confirm that the anaemia is caused by production failure. How is it treated? Treatment for DBA can be with medication (steroids), blood transfusion or bone marrow transplantation. If an unaffected sibling is identified ideally prenatally (when in the womb) cord blood, which is a rich source of bone marrow stem cells, can be transplanted to the affected child. These stem cells, which are collected from the placenta after birth, are able to form bone marrow cells thus correcting the problem with red blood cell production. Further understanding of the cause of DBA is likely to change treatments in the future with more targeted treatment. Inheritance patterns and prenatal diagnosis Inheritance patternsIn most cases DBA occurs sporadically. In subsequent generations the pattern of inheritance is typically autosomal dominant, although there may be variable severity within the family. Prenatal diagnosisPrenatal diagnosis is currently only possible if there is a known mutation, as DBA is usually clinically silent until early infancy. Is there support? DBA UK (Diamond Blackfan Anaemia Support Group) Tel: 0845 094 1548Email: information@diamondblackfan.org.ukWebsite: diamondblackfan.org.uk The Group is a Registered Charity in England and Wales No. 1083179. It provides information and support to the DBA community in the UK by bringing families together, communicating the latest medical information and funding research into causes and cures. The Group holds an annual family weekend. Group details last updated January 2016.
What are the symptoms? Some children with DBA may show physical features such as an extra thumb joint, cleft palate (see entry Cleft Lip and/or Palate) and or a characteristic facial appearance. Many affected children are very short for their age, and may have delayed puberty. Children with DBA otherwise develop normally, and it is unusual for affected children to have learning difficulties.
What are the causes? The anaemia is caused by a failure of the bone marrow to produce red blood cells (‘red cell aplasia’). The exact cause is not clear, but the problem seems to be a fault in one of the early steps of red blood cell production. In up to 25 per cent of affected children there is a fault within a gene called small ribosomal protein 19, or RPS19. Mutations in other parts of the genes which code for ribosomes have more recently been discovered in a further 25 per cent of cases. Ribosomes are very important in helping the cell to function properly. These mutations interfere with the working of the cell, stopping the red cells from being produced. Infection with a particular virus (parvovirus) can cause a switch off of red blood cell production. Nearly always this lasts for such a short time that it goes unnoticed, but infection during pregnancy can sometimes cause severe anaemia in the baby. There is also a condition known as ‘transient erythroblastopenia of childhood’ in which red cell production is temporarily switched off, usually following a viral infection. This is rare in babies, being most common in toddlers and pre-school children. This gets better on its own within a few months, and can sometimes be difficult to tell apart from DBA, except by waiting to see if the anaemia improves on its own.
How is it diagnosed? The diagnosis is easy if there is already an affected child within the family, or the baby has a physical feature of DBA. Otherwise, it is a matter of confirming that the problem lies in a red blood cell production failure, and then to exclude parvovirus infection. Preliminary blood tests will show if too few red blood cells are being produced. The next step is for a small sample of bone marrow to be taken, to confirm that the anaemia is caused by production failure.
How is it treated? Treatment for DBA can be with medication (steroids), blood transfusion or bone marrow transplantation. If an unaffected sibling is identified ideally prenatally (when in the womb) cord blood, which is a rich source of bone marrow stem cells, can be transplanted to the affected child. These stem cells, which are collected from the placenta after birth, are able to form bone marrow cells thus correcting the problem with red blood cell production. Further understanding of the cause of DBA is likely to change treatments in the future with more targeted treatment.
Inheritance patterns and prenatal diagnosis Inheritance patternsIn most cases DBA occurs sporadically. In subsequent generations the pattern of inheritance is typically autosomal dominant, although there may be variable severity within the family. Prenatal diagnosisPrenatal diagnosis is currently only possible if there is a known mutation, as DBA is usually clinically silent until early infancy.
Is there support? DBA UK (Diamond Blackfan Anaemia Support Group) Tel: 0845 094 1548Email: information@diamondblackfan.org.ukWebsite: diamondblackfan.org.uk The Group is a Registered Charity in England and Wales No. 1083179. It provides information and support to the DBA community in the UK by bringing families together, communicating the latest medical information and funding research into causes and cures. The Group holds an annual family weekend. Group details last updated January 2016.