An Underrecognized Etiology of Infantile Spasms: Mitochondrial Disorder.
Abstract number :
3.080
Submission category :
Year :
2000
Submission ID :
3317
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Namrata S Shah, Wendy G Mitchell, Childrens Hosp Los Angeles, Los Angeles, CA; Childrens Hosp Los Angeles and USC Sch of Medicine, Los Angeles, CA.
RATIONALE:_ Infantile spasms (IS) are generally classified as symptomatic, (structural lesion, metabolic disorder, or previous CNS insult are known) idiopathic (entirely normal infant prior to the onset of IS), and cryptogenic, (suspected underlying CNS or metabolic abnormalities). In most series, cryptogenic IS are common. METHODS: Children with IS evaluated at CHLA from 1995 to 2000 were reviewed retrospectively to determine etiology, with special emphasis on metabolic evaluation for mitochondrial disorders. All infants underwent video-EEG and neuroimaging. A metabolic workup was undertaken if the etiology was unclear from history, neurologic exam and neuroimaging. Metabolic evaluation generally included urine organic acids, blood amino acids, lactate and pyruvate, urine and blood free and total carnitine. Selected infants also had measures of CSF lactate, pyruvate and amino acids. RESULTS:_Fifty-seven infants were reviewed. 34(60%) had symptomatic infantile spasms, secondary to chromosomal syndromes (9%), cerebral dysgenesis (14%), tuberous sclerosis (7%), perinatal infections (9%), prematurity with intraventricular hemorrhage (7%), non-accidental trauma (2%), perinatal asphyxia (9%) and in-utero vascular insult (4%). 23 (40%) had cryptogenic IS. Metabolic testing suggested a mitochondrial disorder in 14 (25%). Mitochondrial disorder was considered proven in 2 (4%), probable in 7 (12%) and possible in 5(9%). The mitochondrial mutation A3243G (MELAS) was found in two infants (identical twins). Infants with probable mitochondrial disorder had significantly elevated serum lactate and pyruvate levels, with organic aciduria and elevated urine carnitine levels. Infants with possible mitochondrial disorder had either elevated lactate and pyruvate or urine carnitine levels with organic aciduria. The remaining 9 (16%) of the cryptogenic group were of undetermined etiology. CONCLUSIONS:_Mitochondrial disorders should be actively sought as an underlying cause of cryptogenic IS, and may be more common than previously appreciated. In this series, proven or suspected mitochondrial disorders accounted for more than 60% of cryptogenic IS.