Metro Manila (CNN Philippines, October 6) — President Rodrigo Duterte revealed Saturday night in Moscow, Russia (Sunday midnight in Manila) that he has a neuromuscular disease, describing it to the crowd of Filipinos as a “nerve malfunction.”

“May talent ako. Magtingin ako sa 'yo, ‘yung isang mata ko bumaba. Tingnan mo maliit ‘yung isa. 'Di ba maliit? Nagsasariling biyahe ‘yan,” Duterte said. “Actually, that's myasthenia gravis. It's a nerve malfunction. I got it from my grandfather. Ganun rin siya. So I believe, really, in genetics.”

[Translation: I have a talent. I can look at you, but my other eye would be moving down. Look, the other eye is smaller. It’s small, right? It moves on its own … Actually it’s myasthenia gravis. It’s a nerve malfunction. I got it from my grandfather. He’s also like this. So I believe, really, in genetics.]

Duterte said this after joking about how he looked at a woman he had a duet with earlier in the program.

“Gusto ko siyang tingnan sa mata. Pero ang mata ko, ‘yung isang mata ko dito sa mata niya, ‘yung isang mata ko, umiikot, kung saan-saan pumupunta,” Duterte said.

[Translation: I want to look at her in the eye. But my eyes, one of my eyes looks at her eyes, while the other one is spinning, it goes everywhere.]

According to the US National Institute of Neurological Disorders and Stroke (NIDS), myasthenia gravis is “a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles, which are responsible for breathing and moving parts of the body, including the arms and legs.”

Often, the disease affects muscles that control eye and eyelid movement, facial expression, chewing, talking and swallowing. It may also affect muscles that control breathing, the neck and limbs.

Its symptoms may include drooping of one or both eyelids, blurred or double vision, a change in facial expression, difficulty swallowing, shortness of breath, impaired speech and weakness in the arms, hands, fingers, legs and neck.

The NIDS said the condition worsens after periods of activity and improves after periods of rest.

It said that the disease is caused by an error in the transmission of nerve impulses to muscles. It is an autoimmune disease wherein antibodies block, alter or destroy receptors for a neurotransmitter that causes muscle contraction.

It added that in many adults with the disease, the thymus gland — that controls immune function which should shrink after puberty — remains large. Some individuals with myasthenia gravis develop tumors in the gland, which are often harmless but can become cancerous.

About 15 to 20 percent of people with the disease experience at least one myasthenic crisis — a medical emergency where the muscles that control breathing weaken to the point that individuals need a ventilator to help them breathe.

“With treatment, most individuals with myasthenia can significantly improve their muscle weakness and lead full lives,” the NIDS said. “Sometimes the severe weakness of myasthenia gravis may cause respiratory failure, which requires immediate emergency medical care.”

A January 2019 poll revealed that more Filipino adults were worried about Duterte’s health and more of them also believed that the President has health problems.

Despite widespread concern, Malacañang has been adamant about needing to release medical bulletins on Duterte.

So the public is left relying on the President himself about his health woes.

So far, he had said he had underwent a biopsy — wherein he said he tested negative for cancer, has daily migraines, Buerger’s Disease, Barrett’s Esophagus and gastroesophageal reflux disease. He also revealed that he is taking sleeping pills and needs “additional oxygen” to breathe while sleeping.