Pregnancy following preimplantation genetic diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

OBJECTIVE: Presentation of a novel case, involving the design and implementation of preimplantation genetic diagnosis (PGD) for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). METHODS: The disease-causing mutation, c.459C>T (R153C) in exon 4 of the Notch3 gene, was previously identified in the affected father. The family already had a pregnancy termination following prenatal diagnosis and chose to undergo PGD. A PGD protocol was designed to include informative, linked short tandem repeat (STR) markers and an intragenic single nucleotide polymorphism (SNP), coupled to mutation identification. Biopsy was performed at day 3 and blastocysts were transferred on day 5 after fertilization. Standard prenatal diagnosis procedures were employed to confirm the PGD results. RESULTS: One blastomere was removed at day 3 from each of eight embryos. Detection of the c.459C>TNotch3 mutation, coupled to informative polymorphic markers, unambiguously identified three unaffected embryos. Blastocyst transfer resulted in a singleton pregnancy and subsequent prenatal diagnosis confirmed that the fetus was disease-free. CONCLUSIONS: Given the dominant, highly penetrant and potentially serious effects of Notch3 mutations, PGD for CADASIL may be considered and implemented as a reproductive option, following proper genetic counseling.

The prenatal diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) by mutation analysis.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an important cause of hereditary stroke. Mutations in the Notch3 gene are clearly causally linked to this progressive vascular disorder. Cerebral ischemic attacks, cognitive decline, strokes, and vascular dementia constitute the major manifestations of this disorder. This report details the prenatal detection of a Notch3 mutation in the fetus of a couple where the father had a known mutation in this gene. This is the first report of a prenatal diagnosis of CADASIL, and another example of a serious, highly penetrant, and relentlessly progressive degenerative genetic disorder presenting decades after birth and for which prenatal diagnosis is an option.

Report on the third EDNAP collaborative STR exercise. European DNA Profiling Group.

This report describes an inter-laboratory exercise completed on behalf of the European DNA Profiling (EDNAP) group. The exercise is one in a series designated to identify STR loci which could be used for harmonisation between participating European forensic science laboratories. Participants were asked to identify the alleles present in five bloodstains at the STR loci HUMTHO1 and HUMVWFA31/A. Two of the stains were prepared from mixtures of two different blood samples. There were no special instructions and each laboratory was requested to use the methodology normally employed for crime case investigations. All participating laboratories achieved the same results for both loci. In addition, the laboratories were also requested to report the results obtained from any other loci which would normally be used in crime case investigations. A comparison of these results showed some inter-laboratory variation.

Assignment of the gene determining human carbonic anhydrase, CAI, to chromosome 8.

A cDNA clone complementary to the mRNA encoding the rabbit erythrocyte specific carbonic anhydrase, CAI, has been used as probe for human CAI sequences in the analysis of DNA from panels of rodent/human somatic cell hybrids. The presence of the human CAI gene in all hybrids correlates with the presence of chromosome 8. Together with published mapping data, this assignment indicates that three CA loci are situated on chromosome 8.

Cloned cDNA for rabbit erythrocyte carbonic anhydrase I: A novel erythrocyte-specific probe to study development in erythroid tissues.

Present understanding of gene expression in erythropoietic tissues is derived solely from studies of the globin genes. Of the three distinct carbonic anhydrase (carbonate dehydratase; carbonate hydro-lyase, EC 4.2.1.1) isozymes, carbonic anhydrase I is erythrocyte-specific and, in humans, is under developmental control. The appearance of carbonic anhydrase I in the erythrocyte late in fetal life follows closely the gamma- to beta-globin switch. In order to study the expression of this erythrocyte-specific nonglobin protein, we set out to isolate a cloned carbonic anhydrase I cDNA. A mixture of 17-base-long synthetic oligonucleotides was used as an in situ hybridization probe to screen a rabbit reticulocyte cDNA library. Two clones were isolated, and the complete nucleotide sequence of the clone with the largest insert was determined and shown to code for carbonic anhydrase I. This clone, designated pRCAI, is near full length and has provided the 40% of the amino acid sequence of rabbit carbonic anhydrase I, which was not known hitherto. The deduced primary structure has revealed potentially significant changes in the vicinity of the active site of the rabbit carbonic anhydrase I when compared with carbonic anhydrase I and II sequences from other species.