A 10-month-old boy who weighs as much as a typical 9-year-old child is potentially in danger of dying as his parents scramble to raise money for potential treatment.
Isabel Pantoja, 24, from the Pacific coast state of Colima, said at first she assumed the baby Luis's growth was down to the fact that "I had good breast milk" but now she is desperately anxious for her son.
At the time of birth, the toddler weighed a perfectly normal 8 pounds but after two months he weighed 22 pounds, sparking concerns about his health.
A number of doctors believe Luis may be suffering from Prader-Willi syndrome, a complex genetic disorder that is caused by the loss of function of specific genes.
Ten-month-old Luis Gonzales and his mother Isabel Pantoja, 24, are pictured at their home in Mexico.
Luis parents, however, share that he does not eat excessively.
Lius' family is now facing several difficulties raising the child as the doctors have considered giving him hormonal treatment, which include injections that cost $555 per shot, despite his father earning just $200 per month, Daily Mail reported.
By the age of two months, he weighed 10kg. However, in a short span of ten months, the baby's weight has shot up to 18kg (40lbs).
They take turns pushing him to the hospital in a decrepit stroller for daily blood tests.
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"It hurts to watch the nurses search among the rolls of fat on his arms for a vein", father Mario Gonzales said.
His family said one-day his pram collapsed due to Luis's hefty sizet.
If so - pending the results of tissue samples being done in the USA - he could be helped with a different kind of hormone shot that would kick-start his metabolic glands.
At the moment, despite being alert and responsive - as full of giggles and gurgles as any baby - Luis Manuel can neither walk nor crawl.
Luis' father, Mario, who works at a local juice plant and is physically fit, finds it exhausting to even carry his young son.
But there is hope.
She is awaiting results but has a theory that he could be helped by hormone injections.
The family's plight came to the attention of Silvia Orozco, a surgeon specializing in nutrition who took an interest in the case.
Orozco said that, rather than Prader-Willi Syndrome, his problem may be this: while pregnant with Luis Manuel, his mother's diet lacked certain nutrients and this caused glands that manage his metabolism to underperform. If this hypothesis turns out to be true, then the hormone shots could well be the solution to Luis' medical condition.