EDINBURG — Doctors testified on Monday in Esteban Villegas’ defense that his infant son Alexander died not of child abuse but of rare vitamin deficiencies complicated by a series of vaccine shots he received weeks before his death.

Villegas, 27, of Alamo, is charged with capital murder in connection with the death of his 10-week-old son. His trial, set in Judge Ed Aparicio’s 92nd state District court, began Jan. 18, and the jury is expected to begin deliberating today.

Villegas was caring for Alexander on Nov. 12, 2003, when he told police he found the child not breathing after a nap.

Doctors who treated Alexander at McAllen Medical Center and Driscoll Children’s Hospital testified that the baby had been violently shaken and struck with a blunt object, citing X-rays that showed fractures to the baby’s skull, arms, ribs and legs. Other tests showed blood in deep layers of the baby’s brain and eyes — signs they say are consistent with and typical of shaken-baby syndrome.

But doctors hired by Villegas’ defense team testified the injuries Alexander suffered can indicate other problems the doctors mistakenly diagnosed as shaken-baby syndrome.

Dr. Jerry Bush, an Atlanta medical doctor with a degree in pharmacology, studied Alexander’s case for 10 months. He said antibiotics that Ana Moya received during her pregnancy may have killed bacteria needed to produce important minerals — particularly vitamins C and K — that strengthen bones, tissues and blood vessels.

Ana Moya testified earlier she was sick often during her pregnancy and experienced a difficult delivery with Alexander.

Vitamin deficiencies can lead to weak blood vessels and leave the potential for internal bleeding — in the brain, eyes, lungs, and gastrointestinal tract, Bush said.

Bush said serious vitamin C deficiency is known as acute infantile scurvy. The disease commonly causes bleeding around the bones and black stools, indicating blood in the stomach or intestines.

The bleeding around the bones could have been mistaken for fractures, primarily in the back portion of the ribs, where other doctors claimed the baby was squeezed. The only bones examined in Alexander’s autopsy were in his skull, not in his body, Bush said.

Pediatrician records show Ana Moya took Alexander to the pediatrician reporting the baby was suffering from constipation. He was also anemic — meaning his blood lacked sufficient iron.

Alexander received six vaccines two weeks before his father found him not breathing. Bush said any sort of stress on a baby that is vitamin C deficient could have further decreased the baby’s vitamin supply. Vaccines, particularly more than one, also can cause negative reactions, such as gastrointestinal problems, constipation, diarrhea, fever, and poor feeding, he said.

Alexander’s pediatrician, Dr. Jorge Kutugata, indicated some of those symptoms when he saw the baby Nov. 4, 2003. Doctors’ records also revealed the baby began to lose weight after he received the vaccines — slipping from 11 pounds in October to 6.8 pounds Nov. 12.

Bush said baby Alexander’s body was already vitamin C deficient at birth and had brittle bones. Ana Moya’s difficult delivery likely added stress to his body.

Bush said Alexander’s body likely experienced "endotoxin shock" that caused his heart to stop working.

"It’s my opinion, with a reasonable degree of medical certainty, given all those vaccines at once, the baby was in such a compromised state that he could not fight off that insult to his system and the endotoxins caused leaking blood vessels, low blood pressure and ultimately cardiopulmonary arrest," he said.

Under questioning by prosecuting Assistant District Attorney Andrew Almaguer, Bush said he thought that if Alexander had been shaken, he would have suffered neck injuries. He also said the signs associated to shaken baby syndrome have not been proven.

Bush received $19,500 over a 10-month period to help in Villegas’ case, he said.

A second doctor hired by the defense also pointed to Alexander’s weight loss after the vaccines as significant.

"We see a baby that has been growing well, thriving well, after the vaccines are administered the baby stops eating and the weight dramatically drops. The baby now has a disease in my opinion," said Dr. Ruben D. Martinez, an OBGYN in Harlingen.

Martinez said he disagreed with other doctors’ testimony that only forceful shaking causes bleeding in baby’s eyeballs. He said a difficult delivery; CPR or bleeding in the brain can cause the hemorrhages.

All the doctors who treated baby Alexander concurred on the diagnosis that he had been abused, Almaguer pointed out.

Martinez said pediatricians are trained to protect children from child abuse and have historically "taken a very aggressive view of shaken baby syndrome." He said they prefer to err on the side of the child rather than to risk overlooking possible abuse.

"All cases diagnosed as shaken baby syndrome were not due to the (baby being) shaken," he said.

Infantile scurvy can manifest itself in the same symptoms and injuries that Alexander sustained, he said.

Martinez said he believed Alexander died from "acute onset scurvy due to the vaccine reactions."

Villegas’ wife and his mother-in-law testified Saturday they do not believe Villegas abused the baby. Family members have attended the trial each day to support Villegas. His attorney Fernando Mancias portrayed Villegas as a loving father with no criminal record or past history of abuse. Several times during the trial, Villegas appeared to cry as doctors’ testimony detailed the baby’s injuries.

The defense’s witnesses will continue testimony at 8:30 a.m. today.