Patient with Fanconi Syndrome (FS) and retinitis pigmentosa (RP) caused by a deletion and duplication of mitochondrial DNA (mtDNA).
BACKGROUND
We report a patient with a highly unusual presentation of a mitochondrial disorder.


METHODS
An 8-year old girl presented with muscular cramps as well as height and weight deceleration. Investigations revealed lactic acidosis, electrolytic imbalance and urinary loss of glucose and electrolytes secondary to proximal renal tubulopathy consistent with Fanconi syndrome (FS). Ophthalmic examination revealed asymptomatic retinitis pigmentosa (RP) with no other ocular manifestations. A mitochondriopathy was suspected and genetic analysis performed.


RESULTS
Southern blotting documented a heteroplasmic mutation of mtDNA with deletion/duplication. Three discrete mitochondrial genomes were detected: normal; deletion of 6.7 kb and a deletion/duplication consisting of 1 normal and 1 deleted genome. The relative proportions varied considerably between tissues.


CONCLUSIONS
The association of FS and RP combines features of Kearns-Sayre syndrome and Pearson marrow-pancreas syndrome, without being typical of either. This highly unusual clinical presentation emphasises the need for systemic investigation of patients with FS and further underlines the importance of mtDNA analysis in patients with unexpected associations of affected tissues.
Pitchon
E M
EM
Jules Gonin Eye Hospital, Lausanne, Switzerland.
Cachat
F
F
Jacquemont
S
S
Hinard
C
C
Borruat
F-X
FX
Schorderet
D F
DF
Morris
M A
MA
Munier
F L
FL
D002648:Child; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005198:Fanconi Syndrome / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D020440:Gene Duplication; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D028361:Mitochondrial Diseases / Q000175:diagnosis / Q000235:genetics*; D012174:Retinitis Pigmentosa / Q000175:diagnosis / Q000235:genetics*
D004272:DNA, Mitochondrial