Pathogenic variants in the ADARB1 gene cause a neurological disorder.
All individuals with the mutation ADARB1 gene have these features:
● Global developmental delay or intellectual disability
○ Usually severe to profound
● Microcephaly
○ At birth or developed postnatal
● Hypotonia
● Severe feeding difficulties
○ Sometimes associated with difficulty gaining weight
● Epilepsy
○ Early infantile-onset, varying with frequency
○ Some intractable to treatment
○ Variable features which may include generalised tonic-clonic seizures, eye deviation, focal twitching of the face, bouts of apnea
○ In some, epilepsy of infancy with migrating focal seizures
Uncommon features that individuals may present include:
● Cortical blindness
● Variable extropia
● Laryngomalacia
● Subglottic stenosis
● High anterior hairline
● Sparse scalp hair
● Cryptorchidism
● Limited voluntary movement
● Hypotonia evolving to hypertonia and spasticity
● Hyperactive deep tendon reflexes
● Bilateral extensor Babinski sign
● Head lag
● Clenched fists
● Torticollis
● Cafe au lait macule
The reported individuals do not share specific facial features. Some individuals present with the following features:
● Plagiocephaly
● Metopic ridging
● Brachycephaly
● Upslanting palpebral fissures
● Thin upper lip
● High arched palate
Structural abnormalities detected on MRI:
● Thinning of the corpus callosum
● Delayed myelination
● Cerebral atrophy
● Progressive volume loss
● Frontal polymicrogryia
ADARB1