Genetics of patent ductus arteriosus

Differences by Altitude in the Frequency of Congenital Heart Defects in Colombia

More evidence is needed that links the diagnosis of different congenital heart diseases (CHD) identified after birth, with intermediate altitudes above sea level in geographically and ethnically diverse populations. Our aim was to estimate relative frequencies of CHD diagnosis by altitude and gender in the pediatric population of 12 cities in Colombia. This was a cross-sectional study based on the information collected between 2008 and 2013 in Colombia, during annual congenital heart disease (CHD) case detection campaigns in the post-natal period. All children underwent physical examination, pulse-oximetry, and echocardiography. The odds ratio (OR) was used as the summary statistic to assess associations with altitude in the relative frequency of CHD diagnosis. Data from 5900 children who attended the campaigns were evaluated (54.3 % male), out of which 3309 (56.1 %) were diagnosed with CHD. There were statistically significant differences in the relative distribution of the different CHD by city altitude and gender (p < 0.0001). When compared with sea level, altitudes between 1285 and 3000 m above sea level were associated with increased Patent Ductus Arteriosus (PDA) (ORmh 1.68, 95 % CI 1.34-2.09; p < 0.0001) and left ventricular outflow tract obstruction (LVOTO) diagnoses (ORmh 2.06, 95 % CI 1.63-2.61; p < 0.0001), while the opposite was true for right ventricular outflow tract (RVOTO) diagnosis (OR 0.60; 95 % CI 0.49-0.74, p < 0.0001). These associations were not modified by gender differences. In a geographically and ethnically diverse population, altitudes between 1285 and 3000 m above sea level carried an independent and clinically important excess diagnostic risk of PDA and of LVOTO, when compared to all other CHD.

Genetics of patent ductus arteriosus susceptibility and treatment

The ductus arteriosus is a vital fetal structure designed to close shortly after birth. Although many physiologic and pharmacologic investigations have characterized the closure of this structure, genetic studies of persistent patency of the ductus arteriosus (patent ductus arteriosus, PDA) are relatively recent. Progress in the identification of specific genes associated with PDA is well behind that of many adult-onset diseases because of several reasons ranging from the lack of large biorepositories for this unique population to the belief that any genetic contribution to PDA is minimal. Viewing the PDA as a complex, developmentally influenced disease with both genetic and environmental risk factors has resulted in initial successes in some genetic studies. We will introduce several genetic approaches, which have been or are currently being applied to the study of PDA, that have been successful in identifying polymorphisms associated with adult diseases. Genetic investigations of PDA will be discussed with respect to heritability, in general, and to specific risk genes. Several animal models that have been used to study PDA-related genes will also be presented. Further advances in discovering genetic variation causing PDA will drive the more rational use of current therapies, and may help identify currently unknown targets for future therapeutic manipulation.

Congenital heart malformations: aetiology and associations

The causes of congenital heart malformations are complex and include a major contribution by genetic factors. These can be considered under the headings of chromosomal, single gene and multifactorial. Almost any degree of autosomal imbalance, whether a full trisomy or a tiny microdeletion, can cause a cardiac malformation. Recent research has identified several developmental genes which play an important role in cardiac formation: these are discussed with regard to laterality, septation and vascular morphogenesis. Hypothetical 'polygenes', which may contribute to non-syndromal 'multifactorial' cardiac malformations have yet to be identified. Well-known cardiac malformation syndrome associations are described and simple guidelines are presented to help in the assessment and investigation of an affected neonate who has additional multiple dysmorphic features.

Variation in severity of cardiac disease in Holt-Oram syndrome

We describe a family with Holt-Oram syndrome (HOS) with variable hand and cardiac manifestations. One affected relative had complex congenital malformations of the heart consisting of an endocardial cushion defect and hypoplasia of the left ventricle. The literature from 1974 to 1995 is reviewed. Atrial septal defect is the most cardiac abnormality (60.3% of 189 cases) occurring singly or in combination with other malformations. Thirty-three individuals (17.5%) of literature cases) have more complex congenital malformations of the heart requiring complicated medical management and extensive cardiac surgery. Many genetic reference sources of HOS indicate that single or less severe cardiac malformations are expected in this disorder. It is important to provide more information about the occurrence and spectrum of severity of malformations of the heart to individuals and families where HOS is present.

Dermatoglyphs in congenital heart disease

The palmar dermatoglyphs of 800 patients with anatomically proven congenital heart disease were compared with prints from 1000 controls. A review of the previous studies revealed major technical deficiencies, and the present study failed to confirm most of the previously reported positive findings. An overall increase in the incidence of hypothenar patterns was found, probably explaining the previous suggestion of increased atd angle in congenital heart disease. A large number of statistical comparisons inevitably produced a few 'significant' results, most of which were inconsistent in various ways. Two percent of cases were found to have rare epidermal ridge malformation, ridge dissociation. The nature of the relationship between this and congenital heart disease is obscure. Claims that there are diagnostically useful dermatoglyphic changes in congenital heart disease can be disregarded.