Clinical Description
SATB2-associated syndrome (SAS) is a multisystem disorder characterized by significant neurodevelopmental compromise with limited or absent speech, behavioral issues, and craniofacial anomalies.
To date, more than 500 individuals have been identified with a pathogenic variant in SATB2 [Bengani et al 2017, Zarate et al 2019, Mouillé et al 2022, Zarate et al 2022, Zarate et al 2024a]. The following description of the phenotypic features associated with this condition is based on these reports.
Table 2.
SATB2-Associated Syndrome: Frequency of Select Features
View in own window
Finding | % of Affected Persons 1 | Comment |
---|
Developmental delay / intellectual disability | 100% | Most commonly in the moderate-to-profound range |
Speech delay | 100% | |
Craniofacial dysmorphism | 84% | |
Dental anomalies | 98% | |
Behavioral issues | 55% | |
Elevated alkaline phosphatase | 62% | |
Cleft palate | 45% | |
Abnormal neuroimaging | 68% | |
Micrognathia | 42% | |
Hypotonia | 59% | |
Feeding difficulties | 68% | |
Low weight | 22% | |
Low bone density | 26% | |
Clinical seizures | 20% | |
- 1.
Complete information was not available for some individuals.
Developmental delay (DD) and intellectual disability (ID). All known individuals with SAS have some degree of developmental delay, often with intellectual disability of variable severity (mild to profound).
Developmental regression and/or cognitive decline has been described once in an adult female with an 8.6-Mb deletion of 2q32.2-q33.1 who progressed from mild to severe intellectual disability and from poor to absent speech between ages six and 12 years [Gregoric Kumperscak et al 2016].
Neurobehavioral/psychiatric/sleep manifestations. A broad spectrum of behavioral findings has been described, including jovial or friendly personality, autistic tendencies, agitation or aggressive outbursts, self-injury, impulsivity, hyperactivity, anxiety, difficulty falling asleep or maintaining sleep, and sensory issues [Bengani et al 2017, Zarate et al 2017, Cotton et al 2020, Bissell et al 2022, Shelley et al 2023]. There is no evidence that affected individuals have a higher rate of sleep apnea compared to the general population; however, electrical status epilepticus in sleep has been reported. Two affected females were described to have Rett syndrome-like phenotypes with limited purposeful hand movements, stereotyped repetitive movements, and bruxism [Lee et al 2016]. Additional behavioral issues include high pain tolerance, obsessive tendencies, and skin picking [Zarate et al 2017].
Other neurologic manifestations
Hypotonia, particularly during infancy (59%)
Clinical seizures (20%)
EEG abnormalities are frequent but may be without clinically recognizable seizures [
Zarate et al 2017,
Lewis et al 2020]. Electroencephalographic anomalies are particularly common during sleep stages and may include electrical status epilepticus in sleep.
Less common neurologic issues include gait abnormalities / ataxia (17%), hypertonicity and/or spasticity (4%), and hyperreflexia (3%).
Neuroimaging. Brain abnormalities, documented in 68% of affected individuals who underwent head MRI, include nonspecific findings. Most commonly, delayed myelination or abnormal white matter hyperintensities are reported [Lewis et al 2020]. Less frequently, described anomalies include enlarged ventricles, agenesis of the corpus callosum, lissencephaly, brain atrophy, and prominent perivascular spaces [Zarate & Fish 2017, Zarate et al 2017, Lewis et al 2020, Lo et al 2022]. Note that these findings are not sufficiently distinct to suggest the diagnosis of SAS.
Dysmorphic facial features are often observed and persist through adulthood. If present, dysmorphic features are nonspecific. The most frequently described features include the following (see ) [Bengani et al 2017, Zarate & Fish 2017, Zarate et al 2017, Zarate et al 2018a, Zarate et al 2021b]:
Facial features of individuals with SATB2-associated syndrome caused by intragenic pathogenic variants in SATB2 (A-D), intragenic deletion of SATB2 (E), and large deletions that include SATB2 and other adjacent genes (F-G). The most consistently reported (more...)
In those with larger 2q33.1 deletions, additional features can include a prominent forehead, high anterior hairline, triangular appearance of the lower face, low-set ears, and/or long face (see ) [Zarate & Fish 2017, Zarate et al 2021b].
Craniofacial anomalies / feeding. The combination of craniofacial issues and hypotonia is the most likely explanation for the high frequency of feeding issues present during infancy and beyond. Thomason et al [2019] established that 68% of individuals with SAS had feeding difficulties, including overstuffing, chewing problems, or pharyngeal dysphagia. These feeding difficulties can be seen even in individuals without a palatal defect.
Dental anomalies. A broad range of dental abnormalities have been reported in the literature [Zarate et al 2017, Scott et al 2019, Li et al 2022, Kurosaka et al 2023] or by families [Zarate et al 2017, Scott et al 2019].
Skeletal findings. A broad range of skeletal issues have been described in individuals with SAS [Zarate et al 2018a, Mouillé et al 2022, Zarate et al 2024b].
Growth restriction. Pre- and postnatal growth restriction, particularly with slower-than-expected weight gain, can be seen in individuals with SAS. Individuals with large contiguous chromosomal deletions encompassing SATB2 have more significant issues with growth. Normative growth curves for individuals with SAS have been published [Zarate et al 2022].
Eye findings. Both strabismus (18%) and refractive errors (8%) have been described.
Cardiovascular. For individuals with intragenic pathogenic variants, cardiovascular findings appear to be minimal. However, in individuals with large deletions involving SATB2 and adjacent genes, aortic dilatation, pulmonary hypertension, and septal defects have been reported. See also Genotype-Phenotype Correlations for cardiovascular issues due to loss of specific adjacent genes.
Genitourinary. Small or undescended testicles, inguinal hernias, and hypospadias have been described in males with large deletions involving SATB2 and adjacent genes.
Ectodermal changes. Thin skin, reduced subcutaneous fat, and thin or sparse hair have been described in some affected individuals with large deletions involving SATB2 and adjacent genes.
Other features. Hypothyroidism has rarely been reported [Zarate et al 2024b]. Families often report other symptoms, including gastrointestinal (constipation or diarrhea) and immunologic issues (frequent infections).