Cardiac septal and valvular dysmorphogenesis in mice heterozygous for mutations in the homeobox gene Nkx2-5.
نویسندگان
چکیده
Heterozygous mutations in the cardiac homeobox gene, NKX2-5, underlie familial cases of atrial septal defect (ASD) with severe atrioventricular conduction block. In this study, mice heterozygous for Nkx2-5-null alleles were assessed for analogous defects. Although ASD occurred only rarely, atrial septal dysmorphogenesis was evident as increased frequencies of patent foramen ovale and septal aneurysm, and decreased length of the septum primum flap valve. These parameters were compounded by genetic background effects, and in the 129/Sv strain, septal dysmorphogenesis bordered on ASD in 17% of Nkx2-5 heterozygotes. In a proportion of neonatal heterozygotes, as well as in adults with ASD, we found that the size of the foramen ovale was significantly enlarged and altered in shape, potentially exposing the normally thin septum primum to excessive hemodynamic forces. Therefore, defective morphogenesis of the septum secundum may be one contributing factor in the generation of patent foramen ovale, septal aneurysm, and certain ASDs. Mild prolongation of P-R interval in females and an increased frequency of stenotic bicuspid aortic valves were also features of the Nkx2-5 heterozygous phenotype. Our data demonstrate that the complex effects of Nkx2-5 haploinsufficiency in mice are weaker but convergent with those in humans. As in the mouse, the phenotype of human NKX2-5 mutations may be modulated by interacting alleles.
منابع مشابه
Cardiac homeobox gene NKX2-5 mutations and congenital heart disease: associations with atrial septal defect and hypoplastic left heart syndrome.
OBJECTIVES We sought to examine the importance of mutations in the cardiac transcription factor gene NKX2-5 in patients with an atrial septal defect (ASD), patent foramen ovale (PFO), or hypoplastic left heart syndrome (HLHS). BACKGROUND Mutations in NKX2-5 have been found in families showing secundum ASD and atrioventricular (AV) conduction block and in some individuals with tetralogy of Fal...
متن کاملAblation of Nkx2-5 at mid-embryonic stage results in premature lethality and cardiac malformation.
AIMS Human congenital heart disease linked to mutations in the homeobox transcription factor, NKX2-5, is characterized by cardiac anomalies, including atrial and ventricular septal defects as well as conduction and occasional defects in contractility. In the mouse, homozygous germline deletion of Nkx2-5 gene results in death around E10.5. It is, however, not established whether Nkx2-5 is necess...
متن کاملMutations in the cardiac transcription factor NKX2.5 affect diverse cardiac developmental pathways.
Heterozygous mutations in NKX2.5, a homeobox transcription factor, were reported to cause secundum atrial septal defects and result in atrioventricular (AV) conduction block during postnatal life. To further characterize the role of NKX2.5 in cardiac morphogenesis, we sought additional mutations in groups of probands with cardiac anomalies and first-degree AV block, idiopathic AV block, or tetr...
متن کاملNovel NKX2-5 mutations responsible for congenital heart disease.
Congenital heart disease (CHD) is the most common birth defect and is the leading cause of infant morbidity and mortality resulting from birth defects. Increasing evidence demonstrates that genetic variation in the NKX2-5 gene, which encodes a homeobox-containing transcription factor crucial to cardiogenesis, is an important molecular determinant for CHD. Nevertheless, the genetic compone...
متن کاملGenetics of Congenital Heart Defects: The NKX2-5 Gene, a Key Player.
Congenital heart defects (CHDs) represent the biggest fraction of morbid congenital anomalies worldwide. Owing to their complex inheritance patterns and multifactorial etiologies, these defects are difficult to identify before complete manifestation. Research over the past two decades has established firmly the role of genetics in the development of these congenital defects. While syndromic CHD...
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ورودعنوان ژورنال:
- Circulation research
دوره 87 10 شماره
صفحات -
تاریخ انتشار 2000