Article

Compound heterozygosity for mutations in PAX6 in a patient with complex brain anomaly, neonatal diabetes mellitus, and microophthalmia.

National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
American Journal of Medical Genetics Part A (impact factor: 2.39). 11/2009; 149A(11):2543-6. DOI:10.1002/ajmg.a.33081 pp.2543-6
Source: PubMed

ABSTRACT We report on a patient with trisomy 21, microophthalmia, neonatal diabetes mellitus, hypopituitarism, and a complex structural brain anomaly who was a member of a large bilineal family with eye anomalies. The patient inherited a different mutation in PAX6 from each parent and is the only known living and second reported patient with compound heterozygosity for mutations in PAX6. PAX6 is a transcription factor involved in eye and brain development and has roles in pancreatic and pituitary development. Clinical evaluation of the propositus and his parents demonstrated the effects of mutations of differing severity in multiple individuals.

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  • Article: Mutations in the homeodomain of the human SIX3 gene cause holoprosencephaly.
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    ABSTRACT: Holoprosencephaly (HPE) is a common, severe malformation of the brain that involves separation of the central nervous system into left and right halves. Mild HPE can consist of signs such as a single central incisor, hypotelorism, microcephaly, or other craniofacial findings that can be present with or without associated brain malformations. The aetiology of HPE is extremely heterogeneous, with the proposed participation of a minimum of 12 HPE-associated genetic loci as well as the causal involvement of specific teratogens acting at the earliest stages of neurulation. The HPE2 locus was recently characterized as a 1-Mb interval on human chromosome 2p21 that contained a gene associated with HPE. A minimal critical region was defined by a set of six overlapping deletions and three clustered translocations in HPE patients. We describe here the isolation and characterization of the human homeobox-containing SIX3 gene from the HPE2 minimal critical region (MCR). We show that at least 2 of the HPE-associated translocation breakpoints in 2p21 are less than 200 kb from the 5' end of SIX3. Mutational analysis has identified four different mutations in the homeodomain of SIX3 that are predicted to interfere with transcriptional activation and are associated with HPE. We propose that SIX3 is the HPE2 gene, essential for the development of the anterior neural plate and eye in humans.
    Nature Genetics 07/1999; 22(2):196-8. · 35.53 Impact Factor

Keywords

brain development
 
Clinical evaluation
 
complex structural brain anomaly
 
different mutation
 
eye anomalies
 
large bilineal family
 
multiple individuals
 
mutations
 
neonatal diabetes mellitus
 
parents
 
PAX6
 
pituitary development
 
propositus
 
roles