2q33.1 deletion and SATB2 gene mutation or deletion

chromosome 2

Newly published article discussing 2q33.1 deletion and SATB2 gene mutation or deletion. SATB2-associated syndrome (SAS) is a disorder caused by mutations of the SATB2 gene or deletion of this gene within 2q33.1, a region within the long arm of chromosome 2. The symptoms of SAS include developmental delay, severe intellectual disability, behavioral issues, speech issues, cleft palate, short stature, and facial dysmorphism (abnormal facial structures). Behavioral issues mentioned above may include hyperactivity, sleeping troubles, autism-like symptoms, obsessive behaviors and aggressiveness. Common facial dysmorphism include palatal abnormalities (abnormalities of the palate, the roof of the mouth), micrognathia (undersized jaw), and abnormal dentition (abnormal size, shape, or arrangement of teeth). Other less common symptoms of SAS include decreased bone density, hypotonia (low muscle tone), and epilepsy.

Most data collected on SAS is from young patients. Therefore, there is limited information available on SAS management in adults, and how the disorder may affect patients as they age. This article reports on a number of cases of SAS across a broad range of ages, to help answer the question of how the disorder progresses as patients age.

Analysis of approximately 120 patients in this study confirms that the most common features of this disorder include developmental disabilities with severely limited speech, palatal defects, dental defects, and orthopedic issues. The behavioral issues mentioned above tend to worsen with age. These symptoms occur both in patients with SATB2 mutations and with 2q33.1 deletions that include the SATB2 gene. In larger deletions that affect a greater number of genes, genitourinary anomalies (abnormalities relating to the genital and urinary systems) and cardiac defects were also reported.

SATB2 is important because it regulates a number of other genes involved in the proper development of bodily structures, including the brain, jaw, and skeleton. Therefore, deletions or mutations of SATB2 cause abnormal function of these genes as well, explaining the inadequate development of these structures, leading to the symptoms above.

There is currently no treatment on SAS, and therefore current treatment measures either address the symptoms or are preventative. When palatal issues are present, special emphasis should be put in nutritional support for feeding difficulties caused by this abnormality. Special education for any developmental delay is recommended, particularly speech therapy for those with speech issues. Ongoing surveillance of growth abnormalities, dental abnormalities, and seizures throughout life is also recommended.

Zarate, et al. “Natural history and genotype-phenotype correlations in 72 individuals with SATB2-associated syndrome”. American Journal of Medical Genetics. 2018, v. 176, 925-935.