Smith-Kingsmore Syndrome (SKS)

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MedlinePlus Genetics: ⁴² Smith-Kingsmore syndrome is a neurological disorder characterized by a head that is larger than normal (macrocephaly), intellectual disability, and seizures. In some people with this condition, the ability to speak is delayed or never develops. Some children with Smith-Kingsmore syndrome have features of a behavioral condition called attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorder, which is characterized by impaired communication and social interaction. Structural brain abnormalities may also be present in affected individuals. For example, one or both sides of the brain may be enlarged (hemimegalencephaly or megalencephaly) or have too many ridges on the surface (polymicrogyria), or the fluid-filled spaces near the center of the brain (ventricles) may be bigger than normal (ventriculomegaly).Many people with Smith-Kingsmore syndrome have unusual facial features, such as a triangular face with a pointed chin, a protruding forehead (frontal bossing), widely spaced eyes (hypertelorism) with outside corners that point downward (downslanting palpebral fissures), a flat nasal bridge, or a long space between the nose and upper lip (long philtrum). However, not everyone with Smith-Kingsmore syndrome has distinctive facial features.

MalaCards based summary: Smith-Kingsmore Syndrome, also known as macrocephaly-intellectual disability-neurodevelopmental disorder-small thorax syndrome, is related to alacrima, achalasia, and mental retardation syndrome and contractures, pterygia, and spondylocarpotarsal fusion syndrome 1a. An important gene associated with Smith-Kingsmore Syndrome is MTOR (Mechanistic Target Of Rapamycin Kinase). Affiliated tissues include brain, pons and bone marrow, and related phenotypes are macrocephaly and intellectual disability

Orphanet: ⁵⁸ A rare multiple congenital anomalies/dysmorphic syndrome with intellectual disability, characterized by macrocephaly, intellectual disability, seizures, dysmorphic facial features (including tall forehead, downslanting palpebral fissures, hypertelorism, depressed nasal bridge, and macrostomia), megalencephaly, and small thorax. Other reported features are umbilical hernia, muscular hypotonia, global developmental delay, autistic behavior, and café-au-lait spots, among others.

OMIM®: ⁵⁷ Smith-Kingsmore syndrome is a rare autosomal dominant syndromic intellectual disability syndrome characterized by macrocephaly, seizures, umbilical hernia, and facial dysmorphic features including frontal bossing, midface hypoplasia, small chin, hypertelorism with downslanting palpebral fissures, depressed nasal bridge, smooth philtrum, and thin upper lip (Smith et al., 2013; Baynam et al., 2015). (616638) (Updated 24-Oct-2022)

UniProtKB/Swiss-Prot: ⁷³ An autosomal dominant syndrome characterized by intellectual disability, macrocephaly, seizures, umbilical hernia, and facial dysmorphic features.

Clinical features from OMIM®:

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