Myelodysplastic syndrome (MDS)
A group of bone-marrow disorders in which the marrow makes blood cells that are abnormal (dysplastic) and don't work properly, so blood counts fall despite a busy marrow. Mostly affecting older adults, MDS causes anaemia and low counts and carries a risk of progressing to leukaemia.
What it is
Myelodysplastic syndromes are a group of conditions in which the bone-marrow stem cells become abnormal and produce blood cells that are poorly formed (dysplastic) and function badly, and often die before or soon after entering the blood. The paradox of MDS is that the marrow is usually full or overactive, yet the blood counts are low — because the cells being made are defective and don't survive. This 'ineffective haematopoiesis' most commonly shows first as anaemia (often with a raised MCV, so the red cells are large), but the white cells and platelets can be low too, in any combination. MDS mainly affects older adults and can arise on its own or, less often, after previous chemotherapy or radiation. Symptoms come from the low counts: fatigue and breathlessness from anaemia, infections from low neutrophils, and bruising or bleeding from low platelets — though milder cases can be picked up on a routine blood test with no symptoms. The diagnosis needs a bone-marrow biopsy showing the dysplastic changes, and often genetic (cytogenetic) tests that help classify the risk. MDS ranges widely, from indolent forms managed with support to higher-risk disease, and it carries a defined risk of transforming into acute myeloid leukaemia.
Key lab markers
- Haemoglobin — low (anaemia), often with a raised MCV (large red cells).
- Platelets — can be low.
- Neutrophils / white cells — can be low (infection risk); one, two or all three lines may fall.
- Reticulocytes — often inappropriately low for the degree of anaemia.
- Blood film and bone-marrow biopsy — show the dysplastic (abnormally formed) cells; cytogenetics help classify risk.
Symptoms
- Tiredness and breathlessness (from anaemia)
- Frequent or persistent infections (from low neutrophils)
- Easy bruising, bleeding or petechiae (from low platelets)
- Pallor
- Often no symptoms in milder cases, found on a routine blood test
Related lab panels
When to discuss with a doctor
Myelodysplastic syndrome is diagnosed and managed by a haematologist. It is often first suspected when a blood test shows an unexplained anaemia — particularly a large-cell (high-MCV) anaemia that doesn't respond to B12, folate or iron — or when more than one cell line is low without an obvious cause, especially in an older adult. That pattern warrants a blood-film review and referral for a bone-marrow biopsy, which is what confirms the diagnosis and, with genetic testing, defines the risk and guides treatment. Because MDS can slowly worsen or transform into leukaemia, ongoing specialist monitoring matters. Mediora.AI can surface the pattern that raises the question — a large-cell anaemia, or low counts across more than one line with a low reticulocyte response — but interpreting it, and the bone-marrow work-up, belong with a haematologist.