Serotonin transporter role in identifying similarities between SIDS and idiopathic ALTE.
OBJECTIVE
Considering previous genetic studies on sudden infant death syndrome (SIDS) and the role of L/L serotonin transporter (5HTT) genotype and correlated genes monoamine oxidase A (MAOA) and dopamine transporter (DAT) in unexpected death, an investigation was carried out verifying their involvement in apparent life-threatening events (ALTE and idiopathic form [IALTE]), also assessing common molecular basis with SIDS.


METHODS
Differential diagnoses in 76 ALTE infants, distinguishing ALTE from IALTE was elaborated by using clinical-diagnostic data. Genotypes/allelic frequencies of DAT, MAOA, and 5HTT were determined in ALTE and IALTE infants and compared with data obtained from 20 SIDS and 150 controls.


RESULTS
No association was found between DAT polymorphisms and ALTE/IALTE groups either at the genotype or allelic level (P range .11-.94). MAOA genotypes and allele data comparison between ALTE and controls was not significant; IALTE data showed a tendency for genotypes (P = .09) and were statistically significant for alleles (P = .036); however, MAOA significance disappeared once the Bonferroni correction was applied. 5HTT polymorphisms in IALTE remarked the role of L/L genotype (P < .00001) and L (P < .00001), as previously demonstrated in SIDS.


CONCLUSIONS
Considering correspondence between 5HTT and MAOA in IALTE and SIDS, we hypothesize that the 2 syndromes are different expressions of a common ethiopathogenesis. In particular, genetic data suggest SIDS events could derive from IALTE episodes occurred during sleep, and therefore out of parental control. Despite its functional role, results highlight the usefulness of 5HTT as a valuable tracer of SIDS risk in IALTE infants. Owing to the small sample size, the results are to be considered preliminary and should be reevaluated in an independent sample.
Department of Evolutionary and Functional Biology, University of Parma, Parma, Italy.
Laura
L
Filonzi
Cinzia
C
Magnani
Luana
L
Nosetti
Luigi
L
Nespoli
Camilla
C
Borghi
Marina
M
Vaghi
Francesco
F
Nonnis Marzano
D057768:Brief, Resolved, Unexplained Event / Q000235:genetics*; D016022:Case-Control Studies; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008995:Monoamine Oxidase / Q000235:genetics*; D011110:Polymorphism, Genetic; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*; D013398:Sudden Infant Death / Q000235:genetics*
D050483:Dopamine Plasma Membrane Transport Proteins; D005819:Genetic Markers; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D008995:Monoamine Oxidase