(Trisomy 17p11.2, duplication 17p11.2)
Very rare. Sporadic. Contiguous genes syndrome involving the microduplication of the band 11.2 on the short arm of chromosome 17 (17p11.2). The duplication is preferentially paternal in origin and is caused by unequal crossing-over due to homologous recombination between flanking repeat gene clusters. Close to the Smith-Magenis syndrome, (see this topic) caused by a microdeletion of the same part of the chromosome.
The involved chromosome band includes among others the RAI1 gene (retinoic acid inducible 1); depending on the size of the replication, other genes may be included such as SREBF1, DRG2, LLGL1; SHMT1 and ZFP179
- neonatal and infantile muscular hypotonia (90 %);
- swallowing disorders, gastro-esophageal reflux
- cardiac abnormalities (50 %): ASD, VSD, valvular malformations
- moderate facial dysmorphism: wide frontal bossing, triangular face in childhood but oval later; downslanting palpebral fissures
- dental malocclusion
- growth retardation
- respiratory disorders during sleep (80 %): especially obstructive and non-obstructive apneas
- disorders of speech (95 %): elocution difficulties, echolalia
- autistic behaviour (80%) or hyperactivity/attention type disorders (see these terms)
echocardiography; nocturnal oximetry; mental retardation and disorders of behavior; postoperative cardiopulmonary monitoring
- Schluth-Bolard C, Till M, Edery P, Sanlaville D.
Syndromes chromosomiques émergents.
Pathologie Biologie 2008; 56: 380-7.
Updated: October 2018