Estrada's three other children "appeared to be in good general health," an affidavit in the case states, according to the Public Opinion. CBS21 reported that one of the boy's siblings is a 16-year-old girl, though the station did not say if the pair are twins.
The document alleges that the teen was “very frail, gaunt, ribs extremely evident and ravenously hungry.” He “laid in bed in the fetal position in a way that appeared as though he didn't have the ability to stretch out in his bed.”
Investigators wrote in the affidavit that the boy “ruminated his food” at the hospital -- he ate the food, threw it up and then ate it again.
Police described the boy’s actions as eating as though he couldn’t get enough food at home, the newspaper reported.
According to the Mayo Clinic, the precise cause of rumination syndrome is unclear, but it can be related to a number of issues, including developmental disabilities in children or an increase in abdominal pressure.
"Rumination syndrome is more likely to occur in people with anxiety, depression or other psychiatric disorders," the Mayo Clinic website says.
The disorder can lead to weight loss, malnutrition, esophageal damage and other problems.
The court records allege that Estrada had not used any therapy or early intervention for her son since 2005, when he was 3 years old. Police officials said the boy is developmentally delayed and nonverbal.
Fox43 in York reported that Estrada told police her son, who was born in December 2002, weighed 6 pounds at birth. At the time of his last medical visit, in January 2005, he weighed 22 pounds.
When he was next seen by a doctor 14 years later, he weighed only 3 pounds more, the court records show.
The affidavit indicates the teen was seen at a walk-in clinic in February 2019, at which point he weighed 34 pounds, Fox43 said. His weight had dropped by about 5 pounds in April, when he was seen at Penn State Hershey.
It was unclear if Children and Youth Services became involved in the boy’s case during his April visit to the hospital.
The Public Opinion reported that Estrada railed in October at the genetics specialist treating her son, insisting that he "has no medical issues that require hospitalization," the court records show. She "voiced anger" at the specialist and, saying she "did everything" for her son, said she did not understand why she could not treat him at home.
She also could not comprehend why she had no say when he was admitted immediately into acute care at the hospital, the newspaper reported.
The boy gained 2.2 pounds during his first two days of treatment, the court records show. Upon his discharge after about two months of treatment, he weighed 45 pounds.
He had also grown taller while under the hospital’s care.
The police investigation showed that Estrada did not have a primary care provider for the boy. She claimed the boy received medical care through Early Intervention Services, March of Dimes, Keystone Peds and Penn State Hershey, the Public Opinion reported.
She home-schooled her children, and it appeared the teen “had limited interaction outside of the mother and three other children,” the affidavit says.
A specialist with Penn State Hershey was consulted by police on Jan. 13, CBS21 reported. The doctor offered the opinion that the boy's emaciated condition was caused by malnutrition and medical neglect -- and that his mother was to blame.
Estrada "failed to seek appropriate medical care from an early age until he was 16 years of age and failed to appropriately feed him," the affidavit says.
Estrada was jailed on the charges Friday. Her preliminary hearing is scheduled for next week.
The whereabouts of her other three children were not publicly disclosed.