A selective decrease in binding of [(35)S]tert-butylbicyclophosphorothionate was observed in SSADH(-/-) mice at postnatal day 7 that was progressive until the third postnatal week of life when, at the nadir of the decreased [(35)S]tert-butylbicyclophosphorothionate binding, generalized convulsive seizures emerged that rapidly evolved into status epilepticus.