On Thursday, friends, family and fans of the late Prince, born as Prince Nelson Rogers, mourned the pop icon’s death, which has devastated generations of music lovers but so far has remained a mystery to us all. Prince was 57.

Most of us know the late performer for his infectious stage presence and hits such as “Purple Rain,” “Let’s Go Crazy,” and “Kiss,” which charmed and entertained countless audience members over the span of his decades-long career.

It’s unfortunate that, according to reports, Prince had been suffering from the flu for several weeks and was hospitalized briefly for the respiratory condition late last week. The flu can be serious: We know from data out of the Centers for Disease Control and Prevention (CDC) that the respiratory illness hospitalizes more than 200,000 people— and kills about 36,000— each year.

Although information about the singer’s incredible career in the music industry abounds, less public insight into his medical history has come to light.

In April 2009, the late singer talked to People magazine about his struggle with epilepsy, a chronic and incurable neurological disorder that causes affected individuals to experience brain disruptions that lead to seizures varying in frequency and severity.

We also know that the legacy of Prince’s life had been troubled, as the singer and his ex-wife reportedly lost a child shortly after he was born, and that child had been diagnosed with the skeletal abnormality Pfeiffer’s syndrome, an inherited disorder, E! reported in 1997.

According to the National Institutes of Health (NIH), Pfeiffer’s syndrome leads to premature fusion of specific skull bones, causing tracheal and bronchial abnormalities, as well as facial difference. Individuals with the disorder often have bulging and wide-set eyes, a high forehead, an underdeveloped upper jaw, and a beaked nose.

It is an autosomal dominant disease, meaning one copy of the altered gene in each cell is sufficient to cause the disorder.  An affected individual has a 50 percent chance of having a child with the syndrome, which means this is a disorder that is typically inherited from an affected parent. According to the NIH, unaffected parents are rare but do occur occasionally.

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E! reported that Prince and his ex-wife Mayte Garcia-Nelson lost their newborn with the disorder, named “Boy Gregory,” less than  week after his birth. The couple had been married not long before his birth and subsequent passing. Tragically, Garcia-Nelson suffered a miscarriage shortly after the couple’s first son died, and the loss reportedly tore the couple apart, according to The Mirror.

While we don’t know whether any of this previous medical history played a direct role in Prince’s health struggles or his death with the flu, it is true that any individual with underlying chronic medical conditions could have an increased risk of suffering complications of flu-related death.

We also know that people who do not obtain proper care or are inappropriately monitored during a flu attack may develop greater risk of flu attacks, including pneumonias. It is unfortunate that, according to reports, Prince was fighting the flu as he was still doing concerts and traveling in airplanes.

April 7, Prince reportedly canceled two shows due to the flu, but then he insisted on performing again on April 14. Friday, April 15, his plane made an emergency landing, and he was rushed to the hospital, where he stayed for three hours. 

Of course, we will know more as days come about of his life and his cause of death. But for now, all we know is the sorrow his passing brings to all of us that a legend has died. 

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.