Attitudes of genetic counselors towards genetic susceptibility testing in children.

Genetic susceptibility research and testing is leading to an era of personalized medicine. Genetic counselors act as liaisons between the medical genetics community and the public. Understanding the opinions of genetic counselors will be important in developing testing guidelines.

Characterization of mutations in 22 females with X-linked dominant chondrodysplasia punctata (Happle syndrome).

Purpose: Human X-linked dominant chondrodysplasia punctata (CDPX2) or Happle syndrome is associated with mutations in the human emopamil binding protein (EBP), a delta8-delta7-sterol isomerase involved in cholesterol biosynthesis. The purpose of the current study was to determine the spectrum of EBP mutations in females with CDPX2 and the utility of biochemical screening for the disorder by analysis of plasma sterols.

Methods: Genomic sequencing of the coding exons of the human delta8-delta7-sterol isomerase gene was performed on DNA from 26 females with suspected X-linked dominant chondrodysplasia punctata.

X-linked dominant chondrodysplasia punctata (CDPX2) caused by single gene mosaicism in a male.

X-linked dominant chondrodysplasia punctata (CDPX2; Happle syndrome) is recognized almost exclusively in females, who display mosaic and asymmetric features, presumed to arise secondary to random X-inactivation. CDPX2 results from mutation of an X-linked gene coding for sterol-delta(8)-delta(7) isomerase (emopamil binding protein). We describe a boy with clinical features of CDPX2 (including those presumed to arise usually secondary to functional mosaicism in females).

Molecular, biochemical, and phenotypic analysis of a hemizygous male with a severe atypical phenotype for X-linked dominant Conradi-Hunermann-Happle syndrome and a mutation in EBP.

X-linked dominant Conradi-Hunermann-Happle syndrome (CDPX2; MIM 302960) is a rare chondrodysplasia punctata primarily affecting females. CDPX2 is presumed lethal in males, although a few affected males have been reported. CDPX2 is a cholesterol biosynthetic disorder due to 3-beta-hydroxysteroid-delta8,delta7-isomerase deficiency caused by mutations in the emopamil binding protein (EBP) gene.