Mark Gabriel Villiola and her aunt, Kristine Luwansin, 23, died of smoke inhalation.
The boy was declared dead on arrival at the East Avenue Medical Center (EAMC) in Quezon City.
Luwansin was already dead when discovered inside the family residence at 26 Palma street in Barangay Parang, marikina City.
Villiola’s parents, Mark and Donnay Gay and his elder sister, Aera, 3, are currently receiving treatment for third degree burns at the EAMC.
Senior Superintendent Felipe Rojas, Marikina City police chief, said the family was sound asleep when the fire began at the living room of their house at 6:10 a.m. yesterday.
Rojas said the victims were trapped inside the house, unable to escape through the windows which had iron grills.
Local firemen battled the blaze to get inside and search the rooms for the victims.
"Responding firemen found Luwasin’s lifeless body on the floor," Senior Inspector Antonio Razal Jr., Marikina City fire marshal said.
The boy was still breathing when he was rescued along with his parents and elder sister inside one of the rooms.
Neighbors rushed them to the hospital after firefighters led them to safety.
The fire, which reached the first alarm, was declared out some 20 minutes later.
Damage to property was placed at P30,000.
Razal said they are still determining the cause of the fire.