What is Kleefstra syndrome?
Kleefstra syndrome is a genetic condition that exhibits a wide range of symptoms that may affect multiple areas and systems of the body.
The more common symptoms include intellectual disability, low muscle tone, seizures, and characteristic facial features.
This rare disease was officially identified as Kleefstra syndrome in April 2010, making it a recently identified syndrome.
Syndrome Synonyms:
9q Subtelomeric Deletion Syndrome; 9q- Syndrome Chromosome; 9q34.3 Deletion Syndrome; Kleefstra syndrome
What gene change causes Kleefstra syndrome?
Deletions from the EHMT1 gene on chromosome 9 are responsible for the development of the syndrome, however, changes in KMT2C are responsible of type 2 of this syndrome.
The disease is not inherited but the result of de novo deletions. In some cases, a genetic syndrome may be the result of a de-novo mutation and the first case in a family. In this case, this is a new gene mutation which occurs during the reproductive process.
Type 2 is inherited in an autosomal dominant fashion.
What are the main symptoms of Kleefstra syndrome?
The main symptoms, which may vary in severity between individuals, include developmental delay and intellectual disability. Delayed or no speech is characteristic of the syndrome.
Individuals are often born with a high birth weight and obesity in childhood. In adolescence, the syndrome may trigger apathy and or catatonia.
The syndrome may also cause developmental disorders similar to those associated with Autism, as well as other behavioral issues.
Physical conditions of the syndrome include dental abnormalities, low muscle tone, strabismus or squint in the eyes and hearing loss. The hands of individuals with the syndrome may have a single palm crease, in-curving fingers. Incurving feet are also not uncommon.
Other health conditions associated with the syndrome include kidney issues, and connective tissue disorders. Respiratory infections are common, as are seizures and possible brain abnormalities.
Possible clinical traits/features:
Cryptorchidism, Feeding difficulties in infancy, Autosomal dominant inheritance, Thin vermilion border, Autistic behavior, Patent ductus arteriosus, Intellectual disability, Muscular hypotonia, Cleft palate, Atrial septal defect, Abnormality of the dentition, Microcephaly, Hypermetropia, Short stature, Global developmental delay.
How is Kleefstra syndrome diagnosed?
To find out if someone has a diagnosis of Kleefstra syndrome, it is important to have a consultation and evaluation with a clinical genetic specialist. Specialists may also suggest specific genetic testing or other types of tests to help reach a diagnosis. FDNA’s AI technology can help speed up the diagnostic process by analyzing facial features and other health information.
