Dominant-negative ALK2 allele associates with congenital heart defects.
BACKGROUND
Serious congenital heart defects occur as a result of improper atrioventricular septum (AVS) development during embryogenesis. Despite extensive knowledge of the genetic control of AVS development, few genetic lesions have been identified that are responsible for AVS-associated congenital heart defects.


RESULTS
We sequenced 32 genes known to be important in AVS development in patients with AVS defects and identified 11 novel coding single-nucleotide polymorphisms that are predicted to impair protein function. We focused on variants identified in the bone morphogenetic protein receptor, ALK2, and subjected 2 identified variants to functional analysis. The coding single-nucleotide polymorphisms R307L and L343P are heterozygous missense substitutions and were each identified in single individuals. The L343P allele had impaired functional activity as measured by in vitro kinase and bone morphogenetic protein-specific transcriptional response assays and dominant-interfering activity in vivo. In vivo analysis of zebrafish embryos injected with ALK2 L343P RNA revealed improper atrioventricular canal formation.


CONCLUSIONS
These data identify the dominant-negative allele ALK2 L343P in a patient with AVS defects.
Smith
Kelly A
KA
Associate Professor, Cardiac Development and Genetics Group, Hubrecht Institute for Developmental Biology and Stem Cell Research, Uppsalalaan 8, 3584 CT Utrecht, Netherlands.
Joziasse
Irene C
IC
Chocron
Sonja
S
van Dinther
Maarten
M
Guryev
Victor
V
Verhoeven
Manon C
MC
Rehmann
Holger
H
van der Smagt
Jasper J
JJ
Doevendans
Pieter A
PA
Cuppen
Edwin
E
Mulder
Barbara J
BJ
Ten Dijke
Peter
P
Bakkers
Jeroen
J
D030201:Activin Receptors, Type I / Q000235:genetics / Q000378:metabolism*; D000483:Alleles; D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D002417:Cattle; D002522:Chlorocebus aethiops; D005260:Female; D005799:Genes, Dominant; D006321:Heart / Q000196:embryology / Q000503:physiopathology; D006343:Heart Septal Defects / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D009206:Myocardium / Q000378:metabolism; D009426:Netherlands; D020641:Polymorphism, Single Nucleotide; D015027:Zebrafish / Q000196:embryology / Q000235:genetics
C425423:ACVR1 protein, human; D030201:Activin Receptors, Type I