X-linked sideroblastic anaemia with ataxia: another mitochondrial disease?
OBJECTIVE
The syndrome of X-linked sideroblastic anaemia with ataxia is rare, described only twice in the literature. The aim was to obtain clinical neurological and haematological data about this rare syndrome throughout adult life.


METHODS
A family is described with two affected brothers and two affected maternal uncles. The family was evaluated clinically. Haematological investigations included full blood count, blood film, iron studies, free erythrocyte protoporphyrin (FEP) concentrations and a bone marrow examination where possible.


RESULTS
Core neurological features included motor delay, ataxia evident from early childhood, and dysarthria. Neurological features were non-progressive until the fifth decade when slow progression became evident. Some family members showed mild spasticity. Patients usually have a mild asymptomatic anaemia or a borderline decreased mean corpuscular volume. Blood film examination showed Pappenheimer bodies. Bone marrow examination showed ring sideroblasts, indicating raised erythrocyte iron. Free erythrocyte protoporphyrin (FEP) concentrations were raised.


CONCLUSIONS
Haematological features are subtle and can be easily overlooked, and individual patients may not display all the abnormal features. X-linked ataxias are rare and incorrect genetic advice may be given if the diagnostic haematological features of X-linked sideroblastic anaemia are overlooked. Males with early onset ataxia should have a haematological evaluation including a blood film, with a bone marrow examination if abnormal blood count indices and measurement of FEP concentrations raise suspicion. The condition has parallels with Pearson's syndrome and Friedreich's ataxia. All three conditions are associated with mitochondrial iron handling defects and ataxia. The human ATP binding cassette gene (hABC7) is a candidate gene and requires further investigation.
Hellier
K D
KD
Wessex Neurological Centre, Southampton General Hospital, Southampton SO16 6YD, UK.
Hatchwell
E
E
Duncombe
A S
AS
Kew
J
J
Hammans
S R
SR
D000368:Aged; D000756:Anemia, Sideroblastic / Q000150:complications / Q000235:genetics*; D001259:Ataxia / Q000150:complications*; D001921:Brain / Q000473:pathology; D005260:Female; D008040:Genetic Linkage / Q000235:genetics*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000235:genetics*; D010375:Pedigree; D014960:X Chromosome / Q000235:genetics*