duplication/inversion 15q11 true true GARD:0005153 duplication/inversion 15q11 MESH:C580205 Invdup(15) This syndrome occurs when there is an inverted duplication of the proximal region of chromosome 15, typically including the unstable region 15q11-q13. A large duplication results in tetrasomy of 15p and partial tetrasomy of 15q. Maternal age at conception is a known risk factor. Patients usually have varying degrees of epilepsy, developmental delays, intellectual impairment, autistic spectrum disorders and minor dysmorphic features. Seizures can include epileptic spasms, and a range of other seizure types (both focal and generalized). This chromosomal abnormality is diagnosed on routine karyotype. FISH is used to confirm that the extra chromosomal material is from chromosome 15q or to establish the diagnosis in the event of an interstitial 15q duplication. tetrasomy 15q MONDO:0018027 Inv dup(15) Orphanet:3306 non-telomeric tetrasomy 15q Isodicentric 15 chromosome idic(15) inverted duplication 15 chromosome 15q tetrasomy non-distal tetrasomy 15q ICD10:Q99.8 Isodicentric chromosome 15 syndrome Duplication/inversion type 15q11 SCTID:723332005 Isodicentric chromosome 15 syndrome is a chromosome abnormality that affects many different parts of the body. As the name suggests, people with this condition have an extra chromosome (called an isodicentric chromosome 15 ) which is made of two pieces of chromosome 15 that are stuck together end-to-end. Although the severity of the condition and the associated features vary from person to person, common signs and symptoms include poor muscle tone in newborns; developmental delay; mild to severe intellectual disability; delayed or absent speech; behavioral abnormalities; and seizures . Most cases of isodicentric chromosome 15 syndrome occur sporadically in people with no family history of the condition. Treatment is based on the signs and symptoms present in each person. chromosomal anomaly