Saturday, August 30, 2008

Dad May Be Hazardous to Your Health

Thursday, August 14, 2008

A New Study on Paternal Age and Achondroplasia and Thanatophroic Dysplasia

Am J Med Genet A. 2008 Aug 12. [Epub ahead of print]
The population-based prevalence of achondroplasia and thanatophoric dysplasia in selected regions of the US.Waller DK, Correa A, Vo TM, Wang Y, Hobbs C, Langlois PH, Pearson K, Romitti PA, Shaw GM, Hecht JT.
Houston Health Science Center, The University of Texas, Houston, Texas.

There have been no large population-based studies of the prevalence of achondroplasia and thanatophroic dysplasia in the United States. This study compared data from seven population-based birth defects monitoring programs in the United States. We also present data on the association between older paternal age and these birth defects, which has been described in earlier studies. The prevalence of achondroplasia ranged from 0.36 to 0.60 per 10,000 livebirths (1/27,780-1/16,670 livebirths). The prevalence of thanatophoric dysplasia ranged from 0.21 to 0.30 per 10,000 livebirths (1/33,330-1/47,620 livebirths). In Texas, fathers that were 25-29, 30-34, 35-39, and >/=40 years of age had significantly increased rates of de novo achondroplasia among their offspring compared with younger fathers. The adjusted prevalence odds ratios were 2.8 (95% CI; 1.2, 6.7), 2.8 (95% CI; 1.0, 7.6), 4.9 (95% CI; 1.7, 14.3), and 5.0 (95% CI; 1.5, 16.1), respectively. Using the same age categories, the crude prevalence odds ratios for de novo cases of thanatophoric dysplasia in Texas were 5.8 (95% CI; 1.7, 9.8), 3.9 (95% CI; 1.1, 6.7), 6.1 (95% CI; 1.6, 10.6), and 10.2 (95% CI; 2.6, 17.8), respectively. These data suggest that thanatophoric dysplasia is one-third to one-half as frequent as achondroplasia. The differences in the prevalence of these conditions across monitoring programs were consistent with random fluctuation. Birth defects monitoring programs may be a good source of ascertainment for population-based studies of achondroplasia and thanatophoric dysplasia, provided that diagnoses are confirmed by review of medical records. (c) 2008 Wiley-Liss, Inc.

PMID: 18698630 [PubMed - as supplied by publisher]


Thursday, August 7, 2008

Early noninvasive prenatal detection of a fetal CRB1 mutation causing Leber congenital amaurosis - Paternally inherited point mutation

1: Mol Vis. 2008 Aug 4;14:1388-94.
Early noninvasive prenatal detection of a fetal CRB1 mutation causing Leber congenital amaurosis.Bustamante-Aragones A, Vallespin E, Rodriguez de Alba M, Trujillo-Tiebas MJ, Gonzalez-Gonzalez C, Diego-Alvarez D, Riveiro-Alvarez R, Lorda-Sanchez I, Ayuso C, Ramos C.
Department of Genetics, Fundacion Jimenez Diaz-Capio, CIBERER, Madrid, Spain.

PURPOSE: Leber congenital amaurosis (LCA) is one of the most severe inherited retinal dystrophies with the earliest age of onset. Mutations in the Crumbs homologue 1 (CRB1; OMIM 600105) gene explain 10%-24% of cases with LCA depending on the population. The aim of the present work was to study a fetal mutation associated to LCA in maternal plasma by a new methodology in the noninvasive prenatal diagnosis field: the denaturing High Performance Liquid Chromatography (dHPLC). METHODS: This study presents the case of a compound heterozygous fetus for two mutations in CRB1 (1q3.1-q32.2). dHPLC and automated DNA sequencing were used to detect the paternally inherited fetal mutation in a maternal plasma sample collected at the 12th week of gestation. To test the detection limit of dHPLC, we made serial dilutions of paternal DNA in control DNA. RESULTS: We were able to detect the presence of the paternally inherited fetal CRB1 mutation in maternal plasma by dHPLC. Moreover, by comparing chromatograms of serial dilutions to the plasma sample, we could ascertain that the percentage of fetal DNA in maternal plasma was at least 2%. However, the detection of the fetal mutation was not possible by automated DNA sequencing. CONCLUSIONS: dHPLC seems to be sensitive enough to detect small amounts of fetal DNA in maternal plasma samples. It could be a useful tool for the noninvasive prenatal detection of paternally inherited point mutations associated with retinopathies.