While his parents were away at a wedding, seven-year-old Seth was dying in his bedroom.

Two Minnesota parents have been charged with neglect after their seven-year-old adopted son died when they refused to seek medical treatment for his illness.

Seth Johnson died in March 2015, suffering from an inflamed pancreas and infections in various wounds on his body. Authorities say his parents, Timothy D. Johnson, 39, and Sarah N. Johnson, 38, refused to seek medical treatment for their son because they had “issues with going to doctors”.

On the final weekend of his life, Seth's parents left him in the care of his 16-year-old brother while they attended a wedding out of town.

On the Sunday morning, the teen called to say Seth wasn't eating, couldn't get out of bed and wasn't talking.

When his parents returned home that night, the 7-year-old was unresponsive. Court documents say they "prayed for his health" before bathing him and putting him to sleep, agreeing to seek medical assistance if he wasn't better when he woke.

In the morning, Seth was "unresponsive on the mattress and covered in vomit". They called 911 and Timothy began CPR.

According to complaints against the couple, detailed by Star Tribune, Seth was declared dead at the scene when emergency medical responders arrived at the Johnson's home.

The seven-year-old's body had bruises on his "face, arms, chest, buttocks and lower torso" and "breaks on his skin on the majority of his body".

According to Seth's parents, in the weeks before his death, his behaviour had changed: he had stopped sleeping, and began developing blisters and marks on his legs. Both Timothy and Sarah told law enforcement that he was "always hurting himself" and would "throw himself down stairs and hit his head".

"The Johnson's acknowledge that, despite the myriad of concerning behavioural changes, they never took [Seth] to a doctor because they had ‘issues with going to doctors,'" court documents stated.

"They were concerned that a doctor would put [Seth] on medications and believed that they got better information from their own research."

The parents were charged last week after an independent review of Seth's death by Hennepin County Attorney Mike Freeman.

Despite the medical examiner concluding that Seth died of acute pancreatitis and possible sepsis, Freeman said a definitive link between Seth's cause of death and the actions of his parents could not be made.

"We spent a year reviewing all the evidence. We consulted with a child-abuse paediatrician who reviewed all of the medical information and investigative files to advise us on this one simple question: Could he link the parents’ actions, or inactions, to Seth developing pancreatitis and dying? He could not," he said in a statement.

Despite originally pursuing the case as a homicide, Freeman said that the charge of neglect of a child resulting in substantial physical harm was the most serious charge for the parents based on the medical results.

They each face up to one year in prison and a fine of up to $3,000 if convicted of the charge when they appear in court on January 31, 2017.