Two brothers, aged five and six, have been fitted with dentures so they can eat without fear of choking, as a rare condition causes their hair, teeth and nails to grow abnormally.
Richard, six, and Lennon McDonald, five, from Corby, Northamptonshire, have the genetic condition Ectodermal Dysplasia (ED).
Their mum Zoe McDonald, 27, has spoken out about their struggles in the hope of raising awareness for the condition.
"Sometimes it's truly heart-breaking," she said. "My son asked for hair for his birthday which was difficult to hear but they understand their condition now.
"In the past some children have asked they why they have vampire teeth, to which they reply 'they're not vampire teeth, they're my teeth.'
"Before I was very protective over anything people would say about them but now I just want to educate people and show off everything my little boys have overcome."
The boys' condition doesn't shorten their life expectancy but they do not have any sweat glands meaning they cannot control their body temperature – which puts them at risk of suffering fatal seizures if they overheat or get too cold.
In August this year, Richard and Lennon had dentures fitted over their teeth in order to help them chew food without choking – another problem related to ED which is worsened because sufferers cannot produce saliva.
"Since having their new teeth they've been able to eat so much easier," said McDonald.
"They get really excited hearing their teeth grind together and are obsessed with hearing their food crunch because they've not had it before.
"Both of my sons were born without teeth, but naturally Richard has only grown six teeth and Lennon only has eight so it was always a problem before."
ED is caused by altered genes that mutate before birth – it is estimated to affect just 7,000 people worldwide.
McDonald explained: "Richard was diagnosed at 16 months old, his skin was very pale, he had no hair, eyebrows and only a few pointed teeth.
"Because he had no teeth his chin had sunk making him look older than he was.
"We were finally told I was a carrier of the Ectodermal Dysplasia gene when I was heavily pregnant with my second child, Lennon, and I was told then that there was a 50% chance I'd pass on the condition onto him.
"It was a worrying time and when Lennon was born, we knew straight away he had the same condition."
McDonald's youngest son, one-year-old Cameron, is not affected by the genetic condition.
McDonald says that because not many people have heard of ED she gets asked a lot of questions about her sons' appearances.
"I was once asked if they had progeria, which is a condition where people age quickly," she said.
"I've also been asked if they had cancer which at first was difficult to hear, but we understand because the condition is not very well known, so we tell them the truth.
"Despite having a lot more to contend with compared to other children their age, my sons never fail to amaze me with how they take everything in their stride."
After her sons were diagnosed with the genetic condition, Zoe and husband Craig, 28, got in touch with the Ectodermal Dysplasia Society who help parents of children with ED.
"The group was incredible they gave us a book so that we could help our children to understand what they were going through as well as funding," said McDonald.
"The book helped address some of the issues that the boys had like why they didn't have many teeth and why their hair didn't grow."
Diana Perry, chief executive of the Ectodermal Dysplasia Society said: "There are more than 150 different syndrome types which have been identified as part of ectodermal dysplasia that vary from one person to the next.
"Approximately six children are diagnosed a year, we have around 550 members of our organisation worldwide.
"ED is genetic, people with ED have a faulty gene which is most often passed on to the next generation, although in some cases it is a new mutation.
"The syndrome produces a series of genetic disorders that can affect the development or function of the teeth, hair, nails and sweat glands.
"It can also affect the skin, retina of the eye, parts of the inner ear, development of fingers and toes, nerves and other parts of the body.
"Individuals with ED face a lifetime of special needs including the need for dentures, an air conditioning unit to moderate their heat, protective developments from sunlight and other adaptations."
Richard and Lennon are both keen gymnasts, but because they were born without sweat glands, they have to be careful not to over exert themselves.
"They can't play outside for too long because their bodies can't produce sweat – meaning that if they overheat they can have a fatal seizure," McDonald explained.
"They overheat or get too cold at any moment which puts them at risk, so at times we'll have one of them underneath the air conditioning unit and the other by the heater.
"We're currently fundraising for a shelter so that my sons can play outside with their friends without us needing to worry about them.
"We're trying to give the boys as normal life as they can have and are just blown away by how they're dealing with their condition."
For more information you can visit www.ectodermalydysplasia.org or email firstname.lastname@example.org
To donate and help the brother's fund their shelter visit: www.gofundme.com/richardandlennon