The clinical characteristics of SIHIWES based on a cohort of 31 individuals include:
- Developmental delay (almost all participants)
- Intellectual disability (85%)
- Hypotonia (50%)
- Macrocephaly (50%)
- Congenital heart anomalies (57%)
- Ophthalmic abnormalities (41%)
- Conductive or sensorineural hearing loss (33%)
- Limb or skeletal anomalies (26%)
- Hypogonadism (65% of males)
- Growth hormone deficiency in three participants.
- Brain anomalies such as ventriculomegaly, hydrocephalus, chiari 1 and corpus callosum dysgenesis are found in 96% of individuals undergoing brain MRI.
- Two individuals were report with moyamoya disease with a congenital stroke or during infancy.
- Most patients have similar dysmorphic features: a high and broad forehead, wide spaced eyes, periorbital fullness, a short nose, small or dysmorphic helices and a squared face.