So far, only two cases (age 4 and 10 years) have been reported in literature.
The major clinical features are:
Global developmental delay apparent from infancy
Behavioral problems
One patient showed decreased stranger anxiety and the other autoagression.
Congenital microcephaly
Leading to a head circumference of -4 SD to - 5D in childhood.
Hearing loss
Bilateral sensorineural hearing loss.
Dysmorphisms
A recognisable facial gestalt including a small forehead, highly arched eyebrows, blepharophimosis, full nasal tip, flat philtrum and a pointed chin.
Penetrance
Penetrance is 100%. So far, both individuals with a heterozygous GoF pathogenic variant in the MATH domain of SPOP manifest intellectual disability and additional clinical features.