Credit: Vintage Tone

Starting a business is, by its very nature, a challenging endeavor, and achieving entrepreneurial success under any circumstances is a great accomplishment. But some startup founders have more obstacles to overcome than applying for a bank loan or learning how to market a product. These seven entrepreneurs defied incredible personal odds — including serious diseases, extreme injuries and even blindness — to start their companies.

Patrick Bet-David (PHP Agency)

Like most entrepreneurs, Patrick Bet-David's childhood strongly influenced his views on pursuing opportunity — but not in the way you might expect. Born in war-torn Iran, Bet-David fled the country with his mother in the late 1980s. They then spent two years in a refugee camp in Germany before immigrating to the United States when Bet-David was 12.

After struggling in every school subject but math, Bet-David joined the army after high school. He served as a member of the 101st Airborne Division for several years, then bounced around among different jobs until he landed a position at financial firm Morgan Stanley. Despite having a head for numbers, he failed to get an interview based on his skills or experience.

"I don't have a four-year degree," Bet-David said. "I got hired at Morgan Stanley because my résumé had a joke in it that made [the branch manager] laugh. He said, 'If you can get me to laugh at your résumé, I want to meet [you].' Then I sold him in the interview."

Despite working his way up at this top financial firm, Bet-David said he was not satisfied. He was bored, and felt like something was missing, he said. That missing piece fell into place when he started his own business, PHP Agency (short for People Helping People), in October 2009. Now, his financial services company has more than 5,500 representatives in 33 states.

PHP Agency offers services such as life insurance, annuities, mutual funds and 401(k)s and has dealt in transactions totaling billions of dollars. The company is one of the fastest-growing financial services firms in the country.

"I never could have predicted this," Bet-David said. "I was the kid that parents told their kids to stay away from, because they thought I would never amount to anything."

Isaac Lidsky (ODC Construction)

Imagine starting and growing a successful business, but never being able to see the fruits of your labor. This is exactly what happened to Isaac Lidsky, who was diagnosed at age 13 with a disease that completely robbed him of his sight by age 25.

"Initially, I was depressed and terrified," Lidsky told Business News Daily. "I had preconceived misconceptions about disabilities and limitations, and I felt helpless. Family, friends and several angels in my life helped me to develop the vision to overcome blindness as I lost my sight."

Though his vision was failing, Lidsky graduated from Harvard College before he turned 20, founded and sold a tech company, and earned a law degree that landed him a job as a Department of Justice lawyer. Today, Lidksy serves as the CEO of home building company ODC Construction, which has built tens of thousands of Florida homes, and which brought in more than $68 million in gross revenue last year.

Lidsky attributes his business success to his ability to let go of his internal fears and take control of his situation.

"I had mental images about blindness and the limitations it would impose upon me and my ability to achieve," he said. "I discovered that those mental images were a self-limiting fiction, not a natural truth about the world.

"At the same time, I learned that the ultimate responsibility for my life and my limitations begins and ends with me," Lidsky continued. "It is my responsibility to proactively identify ... obstacles in my way and to look for solutions. There is no limit to the human ability to adapt or the human imagination to create. There are practical solutions for discrete challenges. It is our responsibility to find them and use them to accomplish what we decide to achieve for ourselves."

Chad Mureta (App Empire)

Chad Mureta was running a real estate business when the unthinkable happened: A devastating car accident left him hospital-bound, nearly taking his arm. His business couldn't continue without him being physically present, but Mureta's mounting medical bills meant he had to find an alternative source of income.

After reading a magazine article about mobile apps during his hospitalization, Mureta decided to try his hand at producing mobile applications. At the time, the industry was relatively new, but he felt the growth potential was worth the risk, he said.

"Lying in my hospital bed, I decided to take a Hail Mary shot and get into this industry," Mureta said. "I needed a new business and decided to jump in with both feet. Immediately, I started sketching out ideas for my own apps on pieces of paper. Soon after, I found a development company and outsourced all work to create my first app."

Mureta took out a loan for $1,800 to produce his first app, Fingerprint Security - Pro. It soon became one of the 50 most popular apps in the App Store, earning him $140,000 in the process. From there, Mureta founded and sold three app companies — Empire Apps, Best Apps and T3 Apps — and currently runs a blog called App Empire. He has produced 46 apps to date, and authored "App Empire: Make Money, Have a Life and Let Technology Work for You" (Wiley, 2012).

Mureta advised other entrepreneurs not to be intimidated by their lack of experience in an industry if they see an opportunity. With a thirst for knowledge and the willingness to find and connect with the right people, anyone can begin to carve out an entrepreneurial path for him or herself, he said.

"I'm still not a tech guy," Mureta said. "I couldn't tell you how to program an app, but I can tell you how to make it a success. I researched the market [and] the consumers, and saw opportunities for people like myself. I kept researching and kept expanding my knowledge to grow my business and income."

William Nobrega (CQS International)

A high percentage of startups end in failure. What happens to the entrepreneurs behind them, the individuals who sank all their time, energy and money into businesses that ultimately went under? While some entrepreneurs land on their feet, others, like William Nobrega, have a more difficult time recovering.

In early 2014, the American entrepreneur was broke and living in a small, windowless room in Hong Kong after his startup had failed. He had a new business idea, but with all funding options exhausted, there didn't seem to be much opportunity to make his new idea a reality. But that didn't stop Nobrega from persevering and working toward his dream.

"As a former member of the U.S. Army Special Forces, I lived by the motto, 'Failure is not an option,'" Nobrega said. "So I did what most successful entrepreneurs have done in the past — I continued to push forward with an unwavering commitment to the mission. We brought on team members with the same passion and dedication, and they have been the backbone of our success. Investors that have dealt with many new ventures can sense intestinal fortitude, which has been critical to securing financing for our new venture."

CQS International, an e-commerce insurance company that utilizes proprietary mobile and location-based technology to generate instant sales, was founded less than a year ago and is already valued at more than $170 million. Nobrega admits that there were "a few miracles along the way" that helped him secure investor funding and get the business going, but none of it would have happened if he had given up on his dream.

"Never quit," Nobrega said. "If you believe, and you really need to believe, then you would be willing to sacrifice everything to achieve the mission. If you are fortunate enough to serve with the right team, they will have the same mentality. You will run into obstacles all along the way, but how you deal with them and how you overcome them will determine your success. A team that's cohesive will work miracles."

Jason Pinchoff (PINCH NYC & The Linda B. Pinchoff Foundation)

Dealing with a health crisis or the death of a family member is never easy, but for Jason Pinchoff, tragedy struck all at once. In 1992, Pinchoff lost his father and sister in a car accident. Later that year, he lost his mother to breast cancer. This series of personal misfortunes led Pinchoff to found the Linda B. Pinchoff Foundation, an organization named for his mother and dedicated to supporting and "bringing a voice" to families affected by cancer.

"My first approach was to work 80 hours a week and not tell anyone what was going on," Pinchoff said. "I realized so many people become silent due to disease-related issues, which is one of the main reasons I launched the foundation. It gave me a chance to use my history to help others."

Through his journey of self-healing, Pinchoff recalled the lessons he learned from his family. He was raised to keep fighting and never allow any situation to stop him, he said. This instilled perseverance, helping him push past his fears and follow his passion — which ultimately led him to start a clothing company, PINCH NYC, to help support the Linda B. Pinchoff Foundation.

"Being an entrepreneur is one of the greatest highs, but it comes with a lot of stress and a lot of worries," Pinchoff said. "You have to be ready for the good and bad ... and never let any of that stop what you believe in and what you are doing. I see too many people who want to start a small business but [fail] because they don't truly have that heart, which no book can teach you. You have to be willing to risk several hard years for great years ahead."

Barry Shore (Dlyte.com)

When businessman and entrepreneur Barry Shore was 55, he was diagnosed with Guillain-Barré syndrome (GBS), a rare neurological disorder that rendered him paralyzed from the neck down. Once a strong and vibrant man, Shore suddenly found himself unable to do anything more than turn his head from side to side. Though most people with the disorder make a full recovery, Shore has been struggling to overcome GBS since his diagnosis in September 2004.

"I can walk with the help of a cane and swim ... but I can no longer live the hustle-and-bustle life of running the daily operations of a business," Shore said. "So instead I use my passion, spirit and creativity to inspire those I work with."

It was that passion, spirit and creativity that led Shore to found Dlyte.com, a gift card e-commerce company, in 2012. He drew on his 20-plus years in the gift card industry to create a business that allows consumers to earn cash-redeemable points for every gift card they purchase from the site.

Throughout his decade-long struggle, Shore has remained optimistic and refused to let his disease stop him from thinking, planning and dreaming.

"You need perseverance," he said. "Stay positive and always think. If you keep trying, the answers will be forthcoming. As Nike says, 'Just do it.'"

Gigi Stetler (RV Fun Club & SoLongPain)

Life hasn't been easy for Gigi Stetler, a single mother who didn't complete high school. Early on in her career, her trusted father-figure mentor betrayed her, and on top of that, she was attacked, stabbed and left for dead in her own apartment. Not only did Stetler live to tell the tale, but she also carved out a niche as a successful female entrepreneur.

An accomplished businesswoman and author of "Unstoppable: Surviving Is Just the Beginning" (JAS Literary Publishing, 2009), Stetler is the sole proprietor of an RV dealership, working in a heavily male-dominated industry. Recently, she founded the country's first and only RV membership club, the RV Fun Club, and has also launched an all-natural supplement line called SoLongPain.

"It was very early on in my life that I had to come across hurdles," Stetler said. It was "sink or swim, and sinking wasn't an option. What kept me going was an inner drive, an inner hunger to prove to myself and others that anything is possible. Yes, there came many obstacles, but I never stopped. I always found a way to move around the obstacle."

Stetler said that many individuals, especially those who suffer personal tragedies or lose their jobs or businesses, feel defeated and want to quit on their dreams. But this, she said, is the wrong approach to take.

"Don't give up, don't give in — just get back up and start rebuilding your life as quickly as possible," Stetler said. "If you're having a bad day, take your right hand and put it across your heart. If it's still beating, then be grateful and make it happen."

Additional reporting by Dave Mielach, Business News Daily social media specialist.