Postma group – Uncovering genetic causes in rare (congenital) diseases

We aim to identify the underlying genetic causes in rare (congenital) diseases in order to better understand the pathophysiology of the disease and help improve genetic counseling and therapy. To this end we employ state-of-the-art genomic and bioinformatics techniques.

Contact: A.V. Postma (

Research overview

1. Genetics of Congenital Heart Disease

Congenital heart disease (CHD) is the most common type of birth defect, accounting for one-third of all major congenital anomalies. Worldwide, 1.35 million infants are born with CHD each year. In the Netherlands, CHD occurs in 7 per 1000 live births. A broad phenotypic spectrum exists for CHDs. Conotruncal cardiac defects are among the most prevalent and severe. They are associated with severe late complications, requiring lifelong medical care. Tetralogy of Fallot (TOF, consisting of a ventricular septal defect, obstruction of the right ventricular outflow tract, override of the ventricular septum by the aortic root, and right ventricular hypertrophy) and Transposition of the Great Arteries (TGA, characterised by ventriculo-arterial discordance, where the pulmonary artery arises from a morphological left ventricle and the aorta arises from a morphological right ventricle), account for more than half of conotruncal cardiac defects and 5-10% of all CHDs. Although there have been tremendous advances in diagnosis and treatment of congenital heart disease (CHD), our knowledge of causes of CHD is very limited. Recent clinical and basic research has shown the importance of genetic factors in causation of CHD. The novel high-throughput DNA sequencing technologies that have lately become available (namely next-generation sequencing, NGS) are now expected to provide an important impetus for CHD gene discovery, even in cases with sporadic (non-familial) presentation. Some recent successful examples are the identification of a gain-of-function mutation in TBX5, a cardiac transcription factor, and its involvement in atrial fibrillation in the setting of Holt-Oram disease. Two GWAS studies on the common genetics of TOF and ASD type II and the identification of MYH7 mutations as a cause of Ebsteins anomaly, and TAB2 mutations in patients with outflow tract defects.

Current major focusses of our group for CHD genetics are:

  • Transposition of the Great Arteries
  • Tetralogy of Fallot
  • Familial (consanguineous) CHD

2. Genetics of rare developmental syndromes/diseases

Congenital cardiac and neural tube defects account for 21 percent of late stage fetal or neonatal loss. Chromosomal aberrations commonly contributing to fetal demise are routinely identified via karyotype or comparative genome hybridization (CGH) array analysis; however, these techniques do not identify single nucleotide changes, thus many affected pregnancies remain without a genetic diagnosis. To understand what the genetic cause is for these syndromes we use traditional genetic methods such as linkage analysis or homozygosity analysis, coupled to whole exome or genome sequencing (WES/WGS) and other data sources in the hope to uncover the causal variant(s). Case in point, we were the first to describe a novel syndrome including sacral agenesis, abnormal ossification of the vertebral bodies and a persistent notochordal canal and to provide evidence that homozygous mutations in the T/Brachyury gene underlie this syndrome. Another recent success story was the linking of the SIRT6 gene, a  chromatin-associated protein, to a syndrome involving perinatal loss of life due to a number of severe neurodevelopmental and cardiac anomalies.

Publications, google scholar:

Peer-reviewer profile, publon:

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Figure 1. Schematic representation of a human heart with Transposition of the Great Arteries (TGA). Newborns with TGA have two separate blood flow circuits — one that circulates oxygen-poor (blue) blood from the body back to the body, and another that recirculates oxygen-rich (red) blood from the lungs back to the lungs, which is usually a fatal situation if not operated on immediately.

Figure 2. Locus zoom plot from our genome-wide association study of patients with atrial septal defects type II (ASD II) that uncovered one major locus for this disease in humans on chromosome 4p16.

Figure 3. Example of developmental genetics in which linkage and whole exome sequencing analysis was coupled to uncover a mutation in the T/Brachyury gene causing a novel syndrome.


Aho Ilgun
Doris Milosavljevic
Rajiv Mohan
Francesco Russo


For publications by this research group, click here.