Abstract
An identical homozygous missense variant in EIF3F, identified
through a large-scale genome-wide sequencing approach, was reported as
causative in nine individuals with a neurodevelopmental disorder,
characterized by variable intellectual disability, epilepsy, behavioral
problems and sensorineural hearing-loss. To delineate and expand the
phenotypic and molecular spectrum of EIF3F-related
neurodevelopmental disorder, we examined 21 affected individuals,
homozygous (20/21) or compound heterozygous (1/21) for
c.694T>G/ p.(Phe232Val) in EIF3F. Haplotype analyses
in 12 families suggested that c.694T>G/ p.(Phe232Val) was a
founder variant. All affected individuals had developmental delays
including delayed speech development. About half of the affected
individuals had behavioral problems, altered muscular tone, hearing
loss, and short stature. Moreover, this study suggests that
microcephaly, reduced sensitivity to pain, cleft lip/palate,
gastrointestinal symptoms and ophthalmological symptoms are part of the
phenotypic spectrum. Minor dysmorphic features were observed, although
neither the individuals’ facial nor general appearance were obviously
distinctive. Symptoms in the compound heterozygous individual with an
additional truncating variant were at the severe end of the spectrum in
regard to motor milestones, speech delay, organic problems and pre- and
postnatal growth of body and head, suggesting some genotype-phenotype
correlation. Our study expands the phenotypic and molecular spectrum of
EIF3F-related syndromic neurodevelopmental disorder.