A boy in Nairobi has been diagnosed with a rare condition that makes him hungry all the time, even after eating all day.
Doctors said his weight has ballooned so dangerously that he mostly uses a wheelchair, yet his height is far below that of children his age.
He weighed 103 kilogrammes at about age 11 last year, which is roughly three to four times what a healthy boy his age should typically weigh.
Dr Katherine Oyieke, a paediatric neurologist at the Aga Khan University Hospital in Nairobi (AKUH), and paediatric endocrinologist Dr Menbere Kahssay, confirmed the boy has a rare genetic disorder called Prader-Willi syndrome (PWS).
The brain of people with PWS does not control hunger and fullness, so the person continues to feel hungry even after having food.
The diagnosis offers a rare glimpse into a condition that medical records say affects about one in every 15,000 newborns.
This appears to be among the first confirmed cases from Kenya.
“Currently, his expressive language is limited to a few words; however, it has improved with recently initiated speech therapy. He has challenges with mobility owing to his obesity, and he uses a wheelchair. His sleep pattern is highly irregular and inverse, sleeping only two hours at night and five hours during the day, and he snores while sleeping,” Dr Oyieke and Kahssay said.
The boy was under observation at Aga Khan University Hospital’s paediatric endocrinology clinic since mid-2023, when doctors began tracking his weight and height on growth charts to understand what ailed him.
They only reached a firm diagnosis last year when he had already lost the ability to walk unaided.
Medics said genetic testing is costly and not always available in Kenya, so they first used a 1993 screening tool called the Holm criteria, which scores things like poor feeding as a baby, rapid weight gain, distinctive facial features, developmental delay and small hands and feet.
He scored well above the threshold needed to suspect Prader-Willi syndrome. They later carried out a genetic test that examines the structure of a person’s chromosomes.
The tests showed he had two copies of ‘chromosome 15’ from his mother, instead of receiving one copy from each parent. This genetic change, known as maternal uniparental disomy, confirmed Prader-Willi syndrome.
The doctors said the case shows why children with unusual patterns of obesity need to be assessed for genetic conditions.
“Prader-Willi syndrome is a complex, rare, genetic multisystem disease. Early diagnosis is important for initiating correct care, including detecting hyperphagia to avoid development of morbid obesity and associated comorbidities,” Dr Oyieke’s team said in a report co-authored by Dr Charlotte Hoybye, an endocrinologist at Sweden’s Karolinska Institute.
“A pronounced muscular hypotonia (weak muscles) at birth is strongly associated with PWS and involvement of the neonatologist is key for an early diagnosis,” they said last week on Friday in the BMJ Case Reports journal.
The doctors suspect many cases of Prader-Willi syndrome in low- and middle-income countries (LMICs) remain undiagnosed or unreported because of limited awareness and poor access to genetic testing.
“In LMICs, limited awareness of rare genetic obesity syndromes and poor access to genetic testing frequently delays diagnosis and intervention. This can have serious consequences in conditions such as PWS,” they said.
They advised parents and medics to watch out for babies who feed poorly and seem unusually ‘floppy’ at birth, then later develop a sudden, constant hunger, slow growth and delayed speech or movement milestones.
The Nairobi boy is now receiving care from several specialists, including doctors dealing with hormones, the nervous system, bones, nutrition and child development.
His treatment includes a structured diet, physical activity, vitamin D, physiotherapy, speech therapy and educational support.
“A restricted, supervised diet and regular physical activity are cornerstone treatments in PWS,” the doctors said.
But some treatment remains out of reach because of its cost.
One such is growth hormone to increase height, improve bone density and reduce body fat. The Social Health Insurance schemes do not cover such treatment and there are no local pharmaceutical assistance programmes available.
There has nevertheless been improvement.
After 12 months of follow-up, the child is now sleeping more regularly, communicating better and is able to stand without help. He can also walk short distances with support and has remained free of seizures.
He still largely depends on a wheelchair because of his obesity and limited mobility.
Dr Oyieke’s team confirmed the boy’s parents allowed the case to be documented. Their report is titled “Child with genetically confirmed Prader-Willi syndrome.”
