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2023 ACMG Annual Clinical Genetics Meeting Digital ...
STAG2
is a Novel Genetic Cause of Atelenc ...
STAG2
is a Novel Genetic Cause of Atelencephaly
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Pdf Summary
This document discusses a case study of a patient with atelencephaly, a rare brain malformation. The patient, a 20-year-old pregnant woman, was referred to a fetal care center for evaluation of fetal brain anomalies. Imaging revealed absence of the cerebral hemispheres, consistent with atelencephaly. The pregnancy was complicated by maternal tobacco use and late gestational hypertension. The patient delivered a baby girl who exhibited microcephaly and mild dysmorphic features, including hypotelorism and upslanting palpebral fissures. The baby also had unilateral pre-axial polydactyly.<br /><br />The neonatal course of the baby involved difficulties with feeding, which required the placement of a nasogastric tube. The baby passed the newborn hearing screen and was discharged home at three days of life. The baby remained clinically stable and did not require further hospital admissions or medications. At the 12-month visit, the baby showed increased tone in the extremities and was able to sit independently. Microcephaly and dysmorphic facial features persisted.<br /><br />The patient is currently 21 months old and continues to live at home with her family. She exhibits baseline bradycardia and hypothermia and has had two brief hospital admissions for poor feeding in the setting of urinary tract infections. Whole exome sequencing was performed, which identified a pathogenic nonsense variant in the STAG2 gene, which was not identified on maternal testing. STAG2 is part of the Cohesin complex, which is involved in chromosome segregation, DNA repair and replication, and genome organization. Loss of STAG2 has been associated with various neurodevelopmental conditions.<br /><br />This case study highlights the genetic etiology of atelencephaly and the importance of genetic testing in providing a diagnosis. It also expands the understanding of the STAG2-associated phenotype to include a more severe brain malformation. The findings suggest a common developmental pathway between atelencephaly and holoprosencephaly.
Asset Subtitle
Presenting Author - Julie M. Lander, MD, PhD; Co-Author - Rama S. Ayyala, MD; Co-Author - Cameron Thomas, MD, MS; Co-Author - Robert J. Hopkin, MD;
Meta Tag
Brain/Nervous System
Clinical History
Congenital Anomaly
Delineation of Diseases
Dysmorphology
Etiology
Exome sequencing
Fetal Pathology
Genetic Testing
Genotype-Phenotype Correlations
Identification of Disease Genes
Malformation
Morphogenesis
Natural History
Phenotype
Phenotypic delineation of disorders
Prenatal Diagnosis
Sequencing
Co-Author
Rama S. Ayyala, MD
Co-Author
Cameron Thomas, MD, MS
Co-Author
Robert J. Hopkin, MD
Presenting Author
Julie M. Lander, MD, PhD
Keywords
atelencephaly
brain malformation
fetal care center
microcephaly
dysmorphic features
pre-axial polydactyly
genetic testing
STAG2 gene
Cohesin complex
neurodevelopmental conditions
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