Low melatonin production in infants with a life-threatening event

This studs compares the urinary excretion of the main melatonin metabolite, 6-sulfatoxymelatonin (6SMT), in infants who have and have not experienced a life-threatening event (ALTE). 6SMT was assessed in the following groups of infants: 15 infants with ALTE for whom home monitoring had been recommen ded, 15 infants who had had an abrupt cyanotic apneic event but did not req uire mouth-to-mouth resuscitation, 15 siblings of those who had died from s udden infant death syndrome (SIDS), and 35 age-matched healthy comparison i nfants. All 80 infants were between 48 and 58 weeks of postconceptional age . On a double-blind basis, the total amount of 6SMT excreted over 24 hours and the diurnal rhythm in the rate of 6SMT excretion were assessed using ur ine samples taken from disposable diapers (nappies). The mean daily excreti on of 6SMT was significantly lower in the ALTE (1588 ng/24 hour) than in th e comparison infants (3961 ng/24 hour). No such difference was found betwee n the infants with a cyanotic apneic event (3268 ng/24 hour) and the SIDS s iblings (2962 ng/24 hour). The diurnal 6SMT rhythms in the ALTE infants wer e characterized by lower 24-hour mean and amplitude values, whereas the tim e of peak and nadir excretion rates (07:15 to 08:45 hours and 14:45 to 16:1 5 hours respectively) was similar in all four infant groups. Follow-up of t he ALTE infants, performed 6 to 8 weeks later (59 to 66 weeks of postconcep tional age), revealed that 6SMT excretion increased in all of them, suggest ing a delayed ontogeny rather than permanent deficiency of melatonin produc tion in ALTE.