Cerebral folate deficiency and leukoencephalopathy caused by a mitochondrial DNA deletion.
OBJECTIVE
Our aim was to describe a child with an incomplete form of Kearns-Sayre syndrome who presented profound cerebrospinal fluid (CSF) folate deficiency and his response to folinic acid supplementation


METHODS
CSF 5-methyltetrahydrofolate was analyzed by HPLC with fluorescence detection and mitochondrial DNA deletions by southern blot hybridization.


RESULTS
Cranial magnetic resonance imaging showed a leukoencephalopathy. Profound CSF 5-methyltetrahydrofolate deficiency was observed with normal blood folate values and decreased CSF/serum folate ratio, suggesting a transport defect across the blood-brain barrier. Folinic acid treatment was established, and after 1 year clinical response to folinic supplementation was remarkable, with almost normal white matter image.


CONCLUSIONS
The clinical response after folinic therapy highlights the need for the study of cerebral folate deficiency in patients with mitochondrial disorders and white matter lesions.
Pineda
Merce
M
Servicios de Neuropediatría, Bioquímica y Endocrinología, Hospital Sant Joan de Déu, Clínic, Barcelona, Spain. pineda@hsjdbcn.org
Ormazabal
Aida
A
López-Gallardo
Esther
E
Nascimento
Andres
A
Solano
Abelardo
A
Herrero
Maria D
MD
Vilaseca
Maria A
MA
Briones
Paz
P
Ibáñez
Lourdes
L
Montoya
Julio
J
Artuch
Rafael
R
D001923:Brain Chemistry / Q000235:genetics; D002648:Child; D004252:DNA Mutational Analysis / Q000379:methods; D004272:DNA, Mitochondrial / Q000235:genetics*; D005492:Folic Acid / Q000097:blood / Q000134:cerebrospinal fluid; D005494:Folic Acid Deficiency / Q000150:complications / Q000235:genetics* / Q000473:pathology; D017353:Gene Deletion; D006801:Humans; D007625:Kearns-Sayre Syndrome / Q000134:cerebrospinal fluid / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009132:Muscles / Q000378:metabolism
D004272:DNA, Mitochondrial; D005492:Folic Acid