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Start free with EleplanPLAA-associated neurodevelopmental disorder
ORPHA:521426Malformation syndrome
Also called PLAAND
What it is
A rare genetic neurological disorder characterized by infantile onset of progressive leukoencephalopathy, microcephaly, severe global developmental delay, and spasticity resulting in quadriparesis and posture deformation. Additional features include an abnormally exaggerated startle reflex, seizures, dystonia, and hypomimia or amimia, as well as progressive chest deformities and contractures of large and hyperextensibility of small joints, among others. Thin corpus callosum is a prominent feature in brain imaging, in addition to white matter abnormalities consistent with leukoencephalopathy.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal recessive
- 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%
46- Abnormal cortical gyration
- Abnormal facial shape
- Abnormality of extrapyramidal motor function
- Apnea
- Bulbar palsy
- Cerebellar cortical atrophy
- Cerebral white matter atrophy
- Contractures of the large joints
- Delayed myelination
- Delayed speech and language development
- Dystonia
- Edema of the dorsum of feet
- Edema of the dorsum of hands
- Exaggerated startle response
- Failure to thrive
- Feeding difficulties
- Global developmental delay
- High palate
- Hirsutism
- Hyperextensibility of the finger joints
- Hypoplasia of the corpus callosum
- Hypotonia
- Hypsarrhythmia
- Impaired oropharyngeal swallow response
- Intellectual disability
- Kyphosis
- Leukoencephalopathy
- Limb hypertonia
- Long fingers
- Long philtrum
- Microcephaly
- Micrognathia
- Optic atrophy
- Pectus carinatum
- Postaxial foot polydactyly
- Postaxial hand polydactyly
- Posteriorly rotated ears
- Progressive spastic quadriplegia
- Respiratory insufficiency
- Rigidity
- Rocker bottom foot
- Short nose
- Single transverse palmar crease
- Smooth philtrum
- Tented upper lip vermilion
- Ventriculomegaly
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.
Gene
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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