A genetic mutation that has caused serious muscle weakness of 13 Beduin children
from four families was discovered at Assaf Harofeh Medical Center in
The advance that will help not only such inbred families but
also explains the mechanism of muscle weakness in more common
It was the first time this gene was found in humans; in 2005,
the gene was identified in golden retrievers, but caused a different disease in
Prof. Orit Reish, head of the genetics institute at the hospital,
told The Jerusalem Post on Sunday that the “founder” of the autosomal recessive
genetic defect lived about 50 years ago and was responsible for the “orphan”
disease, which affects only a small number of people. A multi-institute and
multidisciplinary medical team from Israel, the US and Japan worked for several
years on discovering the mutant human gene, whose discovery was just published
in the online, open-access edition of the journal Human Molecular
“The discovery will help the families themselves, because we
have learned that children who inherited the disease from their parents –
healthy carriers who are first cousins – get better at around 14 and 15,” Reish
said. “Soon after they’re born, their muscles are so weak that they often have
to have a feeding tube inserted into their stomachs. The disease is not fatal.
The children have difficulty breastfeeding and motor problems, cry weakly and
suffer from respiratory problems and difficulty walking, but their cognitive
abilities remain normal.
“Later, as teenagers, they are often able to
walk, even if they fall down sometimes. The reason for the improvement is
that other proteins that the children do have makes up for a protein important
in childhood that is missing due to the defective HADC1 gene.”
is not connected to the X or Y sex chromosomes and thus is equally found in boys
A major benefit from the discovery is that from now on, the
disease can be identified in children who undergo a saliva or blood test; they
will not have to go through a MRI or invasive, painful or expensive tests to be
sure. In addition, parents can be assured that their condition will gradually
become better. “Some of the patients are even over 30 years old,” said
Parent carriers can also undergo genetic counseling and decide on
their own if they want to abort an affected fetus. Carriers can also undergo
in-vitro fertilization and pre-implantation genetic diagnosis to ensure that the
embryo implanted in the uterus is not affected by the defect.
no treatment as of yet, but the discovery means that mechanisms that cause other
diseases of congenital myopathy [muscle weakness] that affect larger populations
are understood, and effective medications could be discovered,” the Tzrifin
In numerous US states, Reish said, consanguineous
marriage is not permitted so as to prevent first cousins from marrying and
having a higher chance of giving birth to genetically defective
In Israel, families are discouraged from allowing first cousins
to marry, but it is not prohibited. “I think, however, that inbreeding in the
Beduin community is on the decline as they begin to marry outside their
immediate environment,” she added.
“We have informed the Health Ministry
about the gene and which community is affected, and those suspected of having
the disease were sent to us for study,” Reish said.
Other researchers involved in the discovery included Prof. Ruti Parvari and Dr. Emad Muhammad of Ben-Gurion University and Prof. Val C. Sheffield of the University of Iowa; others came from the Hadassah University Medical Center in Jerusalem and from Japan.