chromosome 1q21.1 duplication syndrome
Findings
No curated finding names chromosome 1q21.1 duplication syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Chromosome 1q21.1 duplication syndrome is a rare condition caused by the presence of an extra copy of a small piece of chromosome 1 in the cells of the body. Signs and symptoms can vary widely among affected individuals. Some individuals have no symptoms, while others may have features such as a large head size (macrocephaly); mild to moderate developmental delay and learning difficulties; autism or autistic-like behavior; heart problems; seizures; and/or and distinctive facial features. This condition can occur sporadically as a de novo mutation (by chance) or can be inherited in an autosomal dominant manner from a parent. Treatment depends on the signs and symptoms present in each individual.
Definition from the Mondo Disease Ontology (MONDO:0012915), read 2026-09-29. CC BY 4.0.
Features
26 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Global developmental delayHPOHP:0001263
- Very frequent (80% to 99% of cases)
- Intellectual disabilityHPOHP:0001249
- Very frequent (80% to 99% of cases)
- Frontal bossingHPOHP:0002007
- Frequent (30% to 79% of cases)
- HypertelorismHPOHP:0000316
- Frequent (30% to 79% of cases)
- MacrocephalyHPOHP:0000256
- Frequent (30% to 79% of cases)
- Arthrogryposis multiplex congenitaHPOHP:0002804
- Occasional (5% to 29% of cases)
- Attention deficit hyperactivity disorder
Show the remaining 14
- GlaucomaHPOHP:0000501
- Occasional (5% to 29% of cases)
- HallucinationsHPOHP:0000738
- Occasional (5% to 29% of cases)
- Hip dislocationHPOHP:0002827
- Occasional (5% to 29% of cases)
- Hip dysplasiaHPOHP:0001385
- Occasional (5% to 29% of cases)
- HydrocephalusHPOHP:0000238
- Occasional (5% to 29% of cases)
- HypertoniaHPOHP:0001276
- Occasional (5% to 29% of cases)
Where it sits
Other names
5 names
Resolves to: chromosome 1q21.1 duplication syndrome
- Also called
- 1q21.1 microduplication syndrome1q21.1 recurrent microduplication (possible susceptibility locus for neurodevelopmental disorders)chromosome 1q21.1 duplication syndrome, isolated casesdup(1)(q21.1)trisomy 1q21.1