A rare immune disease has killed 36 of 54 patients studied at a hospital in Casablanca over the past 26 years, researchers say. The patients had major histocompatibility complex class II deficiency, or MHC-II deficiency. It is a genetic disease that leaves the immune system unable to fight infections properly.
The study looked at 54 patients from 47 families who were diagnosed between 1998 and 2024. All were treated at the national reference centre for primary immunodeficiencies at Ibn Rochd University Hospital in Casablanca.
Thirty-six patients died, giving a mortality rate of 66.7% among the group studied. Fifteen were still alive at the last follow-up, while three could no longer be followed.
The figure does not represent the mortality rate for all people with the disease in Morocco. It covers only patients diagnosed and followed at the Casablanca centre.
The disease often starts in early childhood. The first symptoms appeared at a median age of six months, but patients were not diagnosed until a median age of 19 months.
That delay can be serious. Children can spend more than a year suffering from repeated infections before doctors identify the cause.
More than 96% of the patients had respiratory infections. Almost three-quarters developed pneumonia, and a similar number had problems with growth. Chronic diarrhoea, skin infections, oral thrush, ear infections and autoimmune problems were also common.
A stem-cell transplant is the only treatment that can cure MHC-II deficiency.
Only eight of the 54 patients received one. Five were still alive at the last follow-up, aged between 10 and 24.
The other three died from severe infections.
Patients who had enough medical information available waited a median of 37.5 months between diagnosis and their first transplant.
Doctors also used treatments such as intravenous immunoglobulins and preventive antibiotics. These can help control infections but cannot fix the genetic problem.
Genetic testing found the same deletion in the RFXANK gene in 34 of the 35 patients who were tested. This mutation is particularly common in North Africa.
Consanguinity was recorded in 47 of the 54 families. MHC-II deficiency is an autosomal recessive disease, which means a child must inherit a faulty gene from both parents to develop it.
The researchers called for genetic testing in families at risk and better access to genetic counselling.
They also believe the disease is underdiagnosed. Newborn screening is not available specifically for MHC-II deficiency, while early symptoms can be difficult to recognise and genetic testing and stem-cell transplants remain difficult to access.
Finding affected children earlier and carrying out transplants before serious infections develop could improve their chances of survival.
