Thursday, February 15, 2024

SATB2-associated syndrome

Inspired by a patient

Zarate YA, Bosanko KA, Caffrey AR, Bernstein JA, Martin DM, Williams MS, Berry-Kravis EM, Mark PR, Manning MA, Bhambhani V, Vargas M, Seeley AH, Estrada-Veras JI, van Dooren MF, Schwab M, Vanderver A, Melis D, Alsadah A, Sadler L, Van Esch H, Callewaert B, Oostra A, Maclean J, Dentici ML, Orlando V, Lipson M, Sparagana SP, Maarup TJ, Alsters SI, Brautbar A, Kovitch E, Naidu S, Lees M, Smith DM, Turner L, Raggio V, Spangenberg L, Garcia-Miñaúr S, Roeder ER, Littlejohn RO, Grange D, Pfotenhauer J, Jones MC, Balasubramanian M, Martinez-Monseny A, Blok LS, Gavrilova R, Fish JL. Mutation update for the SATB2 gene. Hum Mutat. 2019 Aug;40(8):1013-1029. doi: 10.1002/humu.23771. Epub 2019 Jun 18. PMID: 31021519.

Abstract

SATB2-associated syndrome (SAS) is an autosomal dominant neurodevelopmental disorder caused by alterations in the SATB2 gene. Here we present a review of published pathogenic variants in the SATB2 gene to date and report 38 novel alterations found in 57 additional previously unreported individuals. Overall, we present a compilation of 120 unique variants identified in 155 unrelated families ranging from single nucleotide coding variants to genomic rearrangements distributed throughout the entire coding region of SATB2. Single nucleotide variants predicted to result in the occurrence of a premature stop codon were the most commonly seen (51/120 = 42.5%) followed by missense variants (31/120 = 25.8%). We review the rather limited functional characterization of pathogenic variants and discuss current understanding of the consequences of the different molecular alterations. We present an expansive phenotypic review along with novel genotype-phenotype correlations. Lastly, we discuss current knowledge of animal models and present future prospects. This review should help provide better guidance for the care of individuals diagnosed with SAS.

Döcker D, Schubach M, Menzel M, Munz M, Spaich C, Biskup S, Bartholdi D. Further delineation of the SATB2 phenotype. Eur J Hum Genet. 2014 Aug;22(8):1034-9. doi: 10.1038/ejhg.2013.280. Epub 2013 Dec 4. PMID: 24301056; PMCID: PMC4350596.

Abstract

SATB2 is an evolutionarily highly conserved chromatin remodeling gene located on chromosome 2q33.1. Vertebrate animal models have shown that Satb2 has a crucial role in craniofacial patterning and osteoblast differentiation, as well as in determining the fates of neuronal projections in the developing neocortex. In humans, chromosomal translocations and deletions of 2q33.1 leading to SATB2 haploinsufficiency are associated with cleft palate (CP), facial dysmorphism and intellectual disability (ID). A single patient carrying a nonsense mutation in SATB2 has been described to date. In this study, we performed trio-exome sequencing in a 3-year-old girl with CP and severely delayed speech development, and her unaffected parents. Previously, the girl had undergone conventional and molecular karyotyping (microarray analysis), as well as targeted analysis for different diseases associated with developmental delay, including Angelman syndrome, Rett syndrome and Fragile X syndrome. No diagnosis could be established. Exome sequencing revealed a de novo nonsense mutation in the SATB2 gene (c.715C>T; p.R239*). The identification of a second patient carrying a de novo nonsense mutation in SATB2 confirms that this gene is essential for normal craniofacial patterning and cognitive development. Based on our data and the literature published so far, we propose a new clinically recognizable syndrome - the SATB2-associated syndrome (SAS). SAS is likely to be underdiagnosed and should be considered in children with ID, severe speech delay, cleft or high-arched palate and abnormal dentition with crowded and irregularly shaped teeth.

Zarate YA, Fish JL. SATB2-associated syndrome: Mechanisms, phenotype, and practical recommendations. Am J Med Genet A. 2017 Feb;173(2):327-337. doi: 10.1002/ajmg.a.38022. Epub 2016 Oct 24. PMID: 27774744; PMCID: PMC5297989.

Abstract

The SATB2-associated syndrome is a recently described syndrome characterized by developmental delay/intellectual disability with absent or limited speech development, craniofacial abnormalities, behavioral problems, dysmorphic features, and palatal and dental abnormalities. Alterations of the SATB2 gene can result from a variety of different mechanisms that include contiguous deletions, intragenic deletions and duplications, translocations with secondary gene disruption, and point mutations. The multisystemic nature of this syndrome demands a multisystemic approach and we propose evaluation and management guidelines. The SATB2-associated syndrome registry has now been started and that will allow gathering further clinical information and refining the provided surveillance recommendations.

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