Novel proton MR spectroscopy findings in adenylosuccinate lyase deficiency.
Adenylosuccinate lyase (ADSL) deficiency is a rare inborn error of metabolism resulting in accumulation of metabolites including succinylaminoimidazole carboxamide riboside (SAICAr) and succinyladenosine (S-Ado) in the brain and other tissues. Patients with ADSL have progressive psychomotor retardation, neonatal seizures, global developmental delay, hypotonia, and autistic features, although variable clinical manifestations may make the initial diagnosis challenging. Two cases of the severe form of the disease are reported here: an 18-month-old boy with global developmental delay, intractable neonatal seizures, progressive cerebral atrophy, and marked hypomyelination, and a 3-month-old girl presenting with microcephaly, neonatal seizures, and marked psychomotor retardation. In both patients in vivo proton magnetic resonance spectroscopy (MRS) showed the presence of S-Ado signal at 8.3 ppm, consistent with a prior report. Interestingly, SAICAr signal was also detectable at 7.5 ppm in affected white matter, which has not been reported in vivo before. A novel splice-site mutation, c.IVS12 + 1/G > C, in the ADSL gene was identified in the second patient. Our findings confirm the utility of in vivo proton MRS in suggesting a specific diagnosis of ADSL deficiency, and also demonstrate an additional in vivo resonance (7.5 ppm) of SAICAr in the cases of severe disease.
Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
Maria
M
Zulfiqar
Doris D M
DD
Lin
Marinette
M
Van der Graaf
Peter B
PB
Barker
Jill A
JA
Fahrner
Sandrine
S
Marie
Eva
E
Morava
Lonneke
L
De Boer
Michel A A P
MA
Willemsen
Eileen
E
Vining
Alena
A
Horská
Udo
U
Engelke
Ron A
RA
Wevers
Gustavo H B
GH
Maegawa
D000241:Adenosine / Q000031:analogs & derivatives / Q000032:analysis; D000264:Adenylosuccinate Lyase / Q000172:deficiency / Q000235:genetics; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000032:analysis; D001321:Autistic Disorder; D001921:Brain / Q000201:enzymology*; D004252:DNA Mutational Analysis; D002658:Developmental Disabilities / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007223:Infant; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D011596:Psychomotor Disorders / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics; D011686:Purine-Pyrimidine Metabolism, Inborn Errors / Q000175:diagnosis* / Q000201:enzymology / Q000235:genetics; D012263:Ribonucleosides / Q000032:analysis
D012263:Ribonucleosides; C043566:succinylaminoimidazole carboxamide riboside; D000620:Aminoimidazole Carboxamide; C043565:succinyladenosine; D000264:Adenylosuccinate Lyase; D000241:Adenosine