A couple in Wisconsin is seeking help as they struggle to understand why their seven-month-old son sometimes turns blue and stops breathing.

According to a fundraising web page created by the family, baby Lynk was born 12 weeks premature. A few weeks after his birth, parents Brittany and Chris Kimmel noticed the baby was turning blue and called 911. That set off a string of hospital visits during which Lynk was diagnosed with hydronephrosis, a condition that causes kidney swelling.

Lynk was also diagnosed with two different heart conditions: patent ductus arteriosus (PDA), which causes abnormal blood flow between two of the major arteries connected to the heart; and atrial septal defect (ASD), which causes a hole in the wall that separates the top two chambers of the baby’s heart.

But Brittany Kimmel told CTVNews.ca in a telephone interview that none of those diagnoses are directly linked to Lynk turning blue. Although he hasn’t had an episode in about a month, Kimmel said her son used to stop breathing and turn blue as often as eight times a week.

Kimmel said doctors have not yet been able to pinpoint the underlying cause of Lynk’s illness.

"They did tests in Green Bay and on Christmas Day they noticed his heart wasn't completely working, so he was transferred down to Madison and we spent a week there,” she told local news station WBAY.  “We've been back there four or five times and we've been to Milwaukee, and nobody knows."

Lynk has endured a battery of tests, including MRI, electrocardiogram, ultrasound and multiple blood tests.  He is currently on four different medications, his mother said. 

“It's just hard, I guess, not knowing what the problem really is,” his father Chris Kimmel said. “You don't know if it's something serious, or if it's minor and maybe it's not a problem; we have no idea."

The couple says the medical bills for Lynk are piling up and they are asking for help. A GoFundMe page has been set up where people can donate money towards the baby’s medical expenses.

Kimmel told CTVNews.ca she is touched by the outpouring of support for her son.

“It’s amazing. I have people messaging me from all over.”