The woman’s two children, a 16-year-old girl, and a 19-year-old man, were treated for smoke inhalation while her 45-year-old husband was also injured, cantonal police said.
Police were contacted after neighbours reported several loud explosions around 2am.
Officers arrived to find a villa on fire and with a collapsed roof.
The father and two children were taken to hospital, police said.
Fire fighters from Bulle were able to extinguish the blaze.
A search for the missing woman continued through the morning, police said.
Neighbouring homes were not affected by the explosions.
Police launched an investigation to determine what caused the incident.
UPDATE: Fribourg cantonal police on Tuesday disclosed that a body, presumed to be of the missing woman, was found by searchers on Monday night.
A formal process of identification was under way, police said in a statement.