THOC6 intellectual disability syndrome is associated with moderate-to-severe developmental delay or intellectual disability; nonspecific dysmorphic facial features (tall forehead, deep-set eyes, short and upslanted palpebral fissures, epicanthal folds, and long nose with low-hanging columella); microcephaly (typically 2-3 SD below the mean); teeth anomalies (dental caries, malocclusion, and supernumerary teeth); cardiac anomalies (most typically atrial and/or ventricular septal defects); prenatal ventriculomegaly and hydrocephalus; cryptorchidism in males; and renal malformations (most commonly unilateral renal agenesis). More rarely, affected individuals may have hypergonadotropic hypogonadism (in females), seizures, poor growth, feeding difficulties, hearing loss, refractive errors and/or other eye abnormalities, vertebral anomalies, micro/retrognathia, and imperforate / anteriorly placed anus.
THOC6 intellectual disability syndrome should be considered in individuals with the following clinical and imaging findings:
• Moderate-to-severe developmental delay (DD) or intellectual disability (ID)
AND
• One or more of the following features presenting in infancy or childhood:
o Microcephaly
o Multiple dental caries and/or dental malocclusion
o Nonspecific dysmorphic features, including tall forehead, deep set eyes, short and upslanted palpebral fissures, epicanthal folds and long nose with low hanging columella
o Cryptorchidism in males
o Structural cardiac anomalies
o Structural renal anomalies
o Ventriculomegaly on brain imaging
THOC6