a chromosome-related disease 9

a chromosome-related disease 9


Kleefstra Syndrome is a rare genetic disease related to an abnormality on chromosome 9. What are the signs? What is support? What is life expectancy? Update with Dr. Laurence Perrin, a clinical geneticist specializing in Kleefstra syndrome practicing at the Robert Debré Hospital in Paris.

Definition: What is Kleefstra Syndrome?

Kleefstra’s syndrome is one rare genetic disease which usually occurs de novo, that is without any of the parents being affected. It is due to either one deletion of a portion of the long arm of chromosome 9or at one mutation of the EHMT1 gene. Its prevalence is estimated at 1/120 000 and it affects both girls and boys.

What are the signs of Kleefstra Syndrome?

Kleefstra Syndrome is essentially characterized by a dysmorphia light facial but characteristic (brachycephaly, wide forehead, unusual shape of eyebrows, malaria hypoplasia, prognathism, short nose) and a intellectual disability extremely variable from patient to patient. “Some children have learning disabilities at school, others have much more severe injuries with one lack of gait or language. Various malformations may also be associated: cardiac, genitourinary, digestive, cerebral, pulmonary, oral, ENT, ophthalmic, endocrinological. Again, their nature differs from subject to subject. Sometimes one epilepsy is found. One can find feeding difficulties and / or a hypotonia in the neonatal period which challenges the medical staff and leads them to perform additional examinations. The assessment can also be initiated because the child has one psychomotor developmental delay“says Dr. Laurence Perrin, a clinical geneticist.

What Causes Kleefstra Syndrome?

There are two possible causes of Kleefstra Syndrome:

  • One deletion of the long arm of chromosome 9;
  • One pathogenic variation of the EHMT1 gene.

How many cases of Kleefstra Syndrome in France?

The prevalence of Kleefstra syndrome is estimated at 1 / 120,000 worldwide, which is rare. “For my part, I am about thirty patients but more and more cases are being detected because techniques to diagnose them are becoming more efficientwhich basically increases the number of cases“says the geneticist.

What is the link between Kleefstra Syndrome and autism?

“Des Autism Spectrum Disorders have been described but their incidence remains poorly understood. Theautism may be a symptom of Kleefstra Syndrome, especially with children who have difficulty communicating, but this is not a generality“informs the specialist.

The diagnosis may be suspected from birth in the face of one hypotonia or various and varied malformations. During early childhood, Kleefstra syndrome may be sought after in case of dysmorphia or psychomotor retardation. In childhood and adulthood, it will be mentioned in the context of neurodevelopmental disorders or facial features. The diagnosis is based, first of all, on the realization of a CGH Array, a research technique to verify the integrity of the chromosomes and highlight thechromosome abnormality 9 (minus small piece on the long arm of chromosome 9). When this deletion is not found, a sequencing of a gene panel or the set of genes, of which the EHMT1 gene is made, in search of a typo on the latter.

What is the treatment for Kleefstra Syndrome?

Currently, it does not exist no curative treatment. Support is based on the treatment of symptomsthe assessment of cognitive difficulties and a educational support. Depending on the disorders observed (neurological, cardiac, eating, ENT, ophthalmic, oral and dental complications …), the subject will be referred to competent professionals.

Management is based on the treatment of symptoms.

What care is available for a child with this syndrome?

“It simply came to our notice then and aims to improve neurodevelopmental disorders. It can include follow-up by one physiotherapista speech therapista psychomotor therapista specialist educator, a child psychiatrista neuropediatrician … Then, according to the child’s cognitive abilities, he can be oriented towards an adapted schooling“, explains Dr. Laurence Perrin.

What is the life expectancy of Kleefstra Syndrome?

“Life expectancy in Kleefstra syndrome remains difficult to determine because the syndrome has not been known for quite some time. It also depends on the associated complications which are different for each patient“says the Kleefstra Syndrome geneticist.

Thanks to Dr. Laurence Perrin, a clinical geneticist specializing in Kleefstra Syndrome at Robert Debré Hospital in Paris.

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