Generalized disturbance of DNA methylation in the uterine decidua in the CBA/J x DBA/2 mouse model of pregnancy failure.

Nonchromosomal pregnancy failure is a common but poorly understood phenomenon. Because recent data have suggested that epigenetic abnormalities such as abnormal placental DNA methylation may play a role in human pregnancy failure, we undertook experiments to test whether decidual and/or placental DNA methylation abnormalities are present in a mouse model of pregnancy failure. A large number of studies have shown that crosses between CBA/J female mice and DBA/2 males result in pregnancies with a high rate of failure/resorption, whereas other crosses with CBA/J females produce normal pregnancies.

Alanine tracts: the expanding story of human illness and trinucleotide repeats.

Expansions of polyglutamine repeats are known to cause a variety of human neurodegenerative diseases. More recently, expansions of alanine tracts, particularly in transcription factor genes, have been shown to cause at least nine human conditions, including mental retardation and malformations of the brain, digits and other structures. Present knowledge suggests that alanine tract expansions generally, but not always, arise through unequal recombination as opposed to replication slippage, the most likely mechanism in other triplet repeat expansions.

Immunolocalization of Zic2 expression in the developing mouse forebrain.

The Zic genes are a family of zinc finger transcription factors defined by their homology with the Drosophila gene, odd-paired (opa). Zic2 has a critical role in forebrain development, as is evidenced by the fact that, in both mice and humans, diminished expression results in the severe forebrain malformation known as holoprosencephaly. Published information indicates that Zic2 expression is most prominent in the dorsal neural tube/spinal cord and in the hindbrain; however, there is no published description of the pattern of expression of Zic2 in the developing forebrain where the main Zic2 associated phenotype occurs.

Possible association of NTDs with a polyhistidine tract polymorphism in the ZIC2 gene.

Neural tube defects (NTDs) and brain malformations represent a common finding in chromosome 13q deletion patients. Hemizygosity for ZIC2, which is located in the 13q32 critical deletion region, results in holoprosencephaly (HPE) in humans, and diminished expression of ZIC2 results in HPE as well as lumbosacral NTDs in mice. Taken together, these observations led us to hypothesize that ZIC2 mutations may be a cause of isolated NTD.