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Start free with EleplanKagami-Ogata syndrome
ORPHA:254519Malformation syndrome
Also called KOS
What it is
Kagami-Ogata syndrome is a rare genetic disease characterized by polyhydramnios (mostly due to placentomegaly), fetal macrosomia, abdominal wall defects, skeletal abnormalities (including bell-shaped thorax, coat-hanger appearance of the ribs and decreased mid to wide thorax diameter ratio in infancy), feeding difficulties and impaired swallowing, dysmorphic features (hairy forehead, full cheeks, protruding philtrum, micrognathia), developmental delay and intellectual disability. Additional features may include kyphoskoliosis, joint contractures, diastasis recti, muscular hypotonia. There is increased risk of hepatoblastoma.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Antenatal, Infancy, Neonatal
- Inheritance
- Autosomal dominant, Not applicable
- 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
Very common80–99%
21- Anteverted nares
- Bell-shaped thorax
- Broad philtrum
- Coat hanger sign of ribs
- Delayed ability to sit
- Depressed nasal bridge
- Dysphagia
- Feeding difficulties
- Full cheeks
- Global developmental delay
- Intellectual disability
- Large placenta
- Limitation of joint mobility
- Micrognathia
- Polyhydramnios
- Poor head control
- Poor suck
- Respiratory failure requiring assisted ventilation
- Short neck
- Thoracic hypoplasia
- Webbed neck
Common30–79%
12Sometimes5–29%
6These 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.
Genes reported in subtypes
Orphanet records these genes on 3 more specific entries under this disorder, not on this entry itself:
A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.
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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