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Start free with EleplanRing chromosome 18 syndrome
ORPHA:1442Malformation syndrome
Also called Ring 18 · Ring chromosome 18
What it is
A rare autosomal anomaly characterized by variable clinical features, most commonly including hypotonia, neonatal feeding and respiratory difficulties, microcephaly, global developmental delay and intellectual disability, growth hormone deficiency, hypothyroidism, hearing loss, aural atresia, dysmorphic facial features and behavioral characteristics.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Antenatal, Infancy, Neonatal
- Classified as
- Malformation syndrome
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Common30–79%
5Sometimes5–29%
9- Abnormal internal genitalia
- Cleft lip
- Delayed myelination
- Hypothyroidism
- Hypotonia
- Intrauterine growth retardation
- Language impairment
- Seizure
and 1 more in this range
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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