SINGAPORE - Growing teens have voracious appetites, but Teo Zi Yee, 17, and David Lucas Soo, 13, feel starved constantly and cannot be left unattended with food.
They have Prader-Willi syndrome (PWS) - a rare neurodevelopmental and genetic condition where the "switch" in the brain that signals fullness never gets flipped on. PWS occurs when part of the genetic material inherited from the father is missing or does not function.
The inability to feel full, causing uncontrollable hunger and overeating, is a hallmark of the syndrome.
Eating often and in large portions leads to quick weight gain, and that leads to morbid obesity, said Associate Professor Angeline Lai, a senior consultant with the Genetics Service at KK Women's and Children's Hospital (KKH).
Complications associated with morbid obesity include obstructive sleep apnoea, diabetes, hypertension and high cholesterol.
"The severity of obesity depends partly on how strictly their food intake is controlled. Often, parents have to lock the kitchen or the pantry cupboard to prevent their children with PWS from excessive eating," Prof Lai said.
"In this respect, early diagnosis should make a difference because from the time the child starts eating solids, parents will have the opportunity to inculcate healthy eating habits and taste buds."
But as a spectrum disorder, the genetic abnormality in PWS also results in a range of other physical, cognitive and behavioural challenges, including developmental and sleep disorders.
Every child is unique and has their own set of challenges and strengths.
"Some children with PWS attend mainstream schools, while others attend special education schools such as APSN and Minds. At the more severe end of the spectrum, some children with PWS may be non-verbal," Prof Lai said.
According to the Global PWS Registry, the syndrome affects between one in 10,000 and one in 30,000 babies born. Males and females are equally affected, as are all races and ethnicities.
KKH diagnoses one to two new cases of PWS each year. Its DNA Diagnostic and Research Laboratory is the only one in Singapore that offers genetic testing on children for the syndrome. The lab is expected to detect more than 99 per cent of PWS cases here.
To ensure that children diagnosed with PWS grow normally, they are given growth hormone treatment, which has been shown to improve height, increase lean body mass and mobility, and decrease fat mass.
Prof Lai said that if the treatment is started at a young age, along with good dietary control, it may reduce and even prevent obesity and the high proportion of fat mass.
"It may also improve motor milestones and some cognitive abilities," she said.
When Zi Yee was born, her body was floppy, like a rag doll, and she was quiet and slept most of the time.
"We found it strange that she had not moved in the last 12 hours. We were told there were two (possible) reasons for this: Side effects from anaesthesia or a possible genetic defect," said her mother, sales executive Lynn Er, 50.
The parents agreed to have their baby's DNA extracted for a fluorescence in situ hybridisation - or Fish - test, which looks for gene changes in cells.
While waiting for the results of the test, which took two weeks, the Teos did exactly what doctors advised against: They turned to Google.
"Google Search turned up a whole list of conditions for floppy babies, and that caused our anxiety to surge," said Zi Yee's father and primary caregiver Teo Wee Kiat, 50, a private tutor.
They were told by Prof Lai that Zi Yee had PWS, and she remained in hospital for a month.
"We were also told that because she did not have a coordinated 'suck and swallow' reflex (to drink milk), she needed to be tube-fed," said Teo.
"It was very trying because the (nasogastric) tube had to be changed regularly, and we had to make sure it went into her stomach and not her lungs."
The couple, who have three daughters - Zi Yee is the middle child - had to get help from Er's mother and Teo's parents.
Er said: "Having Zi Yee changed a lot of our perspectives and expectations. After we had our first daughter, we thought the second would be easy, but little did we know she had PWS. There were the 'why me?' moments, but those passed rather quickly."
Like a typical child with PWS, Zi Yee has small hands and feet and also has scoliosis, an abnormal curving of the spine. She experienced delays in reaching physical activity milestones and is unable to stand or walk on her own.
"She is on growth hormone therapy to improve her muscle mass, and she underwent surgery last year to correct her spine," her mother said.
The Teos also had to make regular trips to KKH for Zi Yee's check-ups and for emergencies.
One particularly harrowing time was when she had severe diarrhoea, which resulted in serious dehydration.
"She was unconscious when we rushed her to the emergency room. I literally thought she had stopped breathing. She was about five or six then," Teo said.
Zi Yee is non-verbal but "she communicates by eye contact, smiling and through hand gestures and chirping sounds", Teo said.
For her education, Zi Yee goes to AWWA School three times a week, and her parents keep her on a strict meal regimen.
"She is obsessed with food, and we stick to a timetable for when she can have her meals, otherwise she would be demanding food all the time," Teo said.
While some people with the syndrome are non-verbal, 13-year-old David loves to make conversation.
"I love soups," the boy told The Straits Times.
David was diagnosed at nine months, after he showed signs of PWS, including low muscle tone.
"Fortunately, he could feed," said his German grandmother Linda Schaumann, 65, who lives near the family.
The eldest of three children, David's appetite changes kicked in as he entered puberty, his grandmother said.
"Before that, his eating was well under control. Now it is easier at home, but it becomes a challenge whenever we are outside. He has since put on a lot of weight," she said.
His mother, Nadja Schaumann, 39, said she has to make sure she controls his intake of food, as David is constantly driven by the urge to eat.
The housewife said she uses the power of distraction. "He goes for Bollywood dancing on Friday nights, does athletics and walks in the park. These activities also keep him healthy and his weight down."
She said they have always made sure he has healthy choices for his meals, such as tofu, vegetable and tempeh (fermented soya beans).
She keeps the kitchen locked, even at night - a norm in homes where people with PWS live.
To help others make sense of his speech, David, who attends a special-needs school, will need speech therapy "for life".
He also spends time at his grandmother's place, and she has to keep her kitchen door locked too, but worries that he will soon be tall enough to unlock it.
Prof Lai said that in adults with PWS, obesity and its complications, such as cardiac disease, are the main causes of death.
"Oher reported causes of death include acute gastric distension with gastric rupture and necrosis, particularly following an eating binge, and choking, especially on hot dogs," she said.
It is not surprising that both Zi Yee's and David's parents worry about their children and have set up trust funds to see them through their future.
"Special-needs adults are often given jobs in the food and beverage industry, but they need to understand that for people with PWS, it is giving in to their food addiction. There needs to be an alternative for them in the working world," the older Schaumann said.
"Many people with PWS overseas are able to function in a group home setting, but because they need supervision to manage their dietary restrictions, few can live independently. Perhaps there should be group homes for adults with PWS set up here."
Teo said: "Insurance companies also need to cover some of the lifelong medication these people with PWS need."
Er added that to be an "all-inclusive society", there must be changing rooms for adults who use diapers and need assistance with changing them.
"The lack of such facilities is the reason why many disabled people tend not to go out," she said.
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This article was first published in The Straits Times. Permission required for reproduction.
