Functional analysis of candidate genes in 2q13 deletion syndrome implicates FBLN7 and TMEM87B deficiency in congenital heart defects and FBLN7 in craniofacial malformations.
Recurrent 2q13 deletion syndrome is associated with incompletely penetrant severe cardiac defects and craniofacial anomalies. We used an atypical, overlapping 1.34 Mb 2q13 deletion in a patient with pathogenically similar congenital heart defects (CHD) to narrow the putative critical region for CHD to 474 kb containing six genes. To determine which of these genes is responsible for severe cardiac and craniofacial defects noted in the patients with the deletions, we used zebrafish morpholino knockdown to test the function of each orthologue during zebrafish development. Morpholino-antisense-mediated depletion of fibulin-7B, a zebrafish orthologue of fibulin-7 (FBLN7), resulted in cardiac hypoplasia, deficient craniofacial cartilage deposition and impaired branchial arch development. TMEM87B depletion likewise resulted in cardiac hypoplasia but with preserved branchial arch development. Depletion of both fibulin-7B and TMEM87B resulted in more severe defects of cardiac development, suggesting that their concurrent loss may enhance the risk of a severe cardiac defect. We postulate that heterozygous loss of FBLN7 and TMEM87B account for some of the clinical features, including cardiac defects and craniofacial abnormalities associated with 2q13 deletion syndrome.
Departments of Pediatrics and mruss@med.umich.edu innis@umich.edu.
Mark W
MW
Russell
Departments of Pediatrics and.
Maide O
MO
Raeker
Departments of Pediatrics and.
Sarah B
SB
Geisler
Human Genetics, University of Michigan Ann Arbor, MI, USA.
Peedikayil E
PE
Thomas
Departments of Pediatrics and.
Tracy A
TA
Simmons
Departments of Pediatrics and.
John A
JA
Bernat
Departments of Pediatrics and.
Thor
T
Thorsson
Departments of Pediatrics and Human Genetics, University of Michigan Ann Arbor, MI, USA mruss@med.umich.edu innis@umich.edu.
Jeffrey W
JW
Innis
D000818:Animals; D002135:Calcium-Binding Proteins / Q000172:deficiency* / Q000235:genetics; D002872:Chromosome Deletion; D002889:Chromosomes, Human, Pair 2; D019465:Craniofacial Abnormalities / Q000235:genetics*; D005260:Female; D006330:Heart Defects, Congenital / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics; D060172:Morpholinos; D016376:Oligonucleotides, Antisense; D013577:Syndrome; D015027:Zebrafish / Q000196:embryology / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics*
D002135:Calcium-Binding Proteins; C524759:FBLN7 protein, human; D008565:Membrane Proteins; D060172:Morpholinos; D016376:Oligonucleotides, Antisense; C532347:TMEM87B protein, human; D029961:Zebrafish Proteins