Congenital creatine transporter deficiency.
BACKGROUND
Two inborn errors of metabolism of creatine synthesis as well as the X-linked creatine transporter (SLC6A8) deficiency have been recognized. This report describes the features of five identified male patients and their female relatives who are carriers of the X-linked creatine transporter deficiency syndrome.


METHODS
Proton MR spectroscopy was used to recognize creatine deficiency in the patients. Molecular analysis of the SLC6A8 gene was performed, confirming the diagnosis of homozygous males and heterozygous females.


RESULTS
We describe four families from a metropolitan area in the U. S. with X-linked creatine transporter deficiency. All affected males present with developmental delay and severe developmental language impairment. Proton MR spectroscopy shows significantly depressed to essentially absent creatine and phosphocreatine in the male patients. Nonsense mutations and amino acid deletions were found in the SLC6A8 gene in the affected families.


CONCLUSIONS
Creatine transporter deficiency may be a more common X-linked genetic disorder than originally presumed. The affected males exhibit mental retardation with severe expressive language impairment.
deGrauw
T J
TJ
Division of Neurology, Cincinnati Children's Hospital Medical Center and College of Medicine, University of Cincinnati, Ohio 45229-3039, USA. Ton.degrauw@cchmc.org
Salomons
G S
GS
Cecil
K M
KM
Chuck
G
G
Newmeyer
A
A
Schapiro
M B
MB
Jakobs
C
C
D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D026901:Membrane Transport Proteins / Q000032:analysis / Q000172:deficiency*; D008661:Metabolism, Inborn Errors / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D010375:Pedigree
D026901:Membrane Transport Proteins; C080679:creatine transporter