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Start free with EleplanWalker-Warburg syndrome
ORPHA:899Disease
Also called HARD syndrome · Hydrocephalus-agyria-retinal dysplasia syndrome · WWS
What it is
A rare form of congenital muscular dystrophy (CMD) associated with severe brain and eye abnormalities. It is the most severe form of CMD.
Key facts
- Prevalence
- 1-9 / 1 000 000 (Europe)
- Age of onset
- Antenatal, Infancy, Neonatal
- Inheritance
- Autosomal recessive
- Classified as
- Disease
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%
29- Abnormal aldolase level
- Abnormal circulating creatine kinase concentration
- Abnormal cortical gyration
- Abnormality of neuronal migration
- Abnormality of the cerebellar vermis
- Abnormal lactate dehydrogenase activity
- Abnormal optic nerve morphology
- Aplasia/Hypoplasia involving the skeletal musculature
- Areflexia
- Cerebellar hypoplasia
- Chorioretinal dysplasia
- Global developmental delay
- Hydrocephalus
- Hyporeflexia
- Hypotonia
- Intellectual disability
- Lissencephaly
- Metatarsus valgus
- Muscle weakness
- Muscular dystrophy
- Optic atrophy
- Pachygyria
- Polymicrogyria
- Retinal detachment
- Retinal dysplasia
- Retinal dystrophy
- Skeletal muscle atrophy
- Specific learning disability
- Ventriculomegaly
Common30–79%
10Sometimes5–29%
11- Bifid uvula
- Cataract
- Cleft palate
- Iris coloboma
- Low-set ears
- Microcephaly
- Microcornea
- Posteriorly rotated ears
and 3 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.
Genes
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.
Benefit programs to look at
Programs whose eligibility touches the same ICD-10 categories. Eligibility is decided by the administering agency, never by this page.
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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