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Biomedical subjects

H Van Bokhoven

Publications and source records attributed to H Van Bokhoven.

8 recordsLinked to original sources

The p63 gene in EEC and other syndromes.

Several autosomal dominantly inherited human syndromes have recently been shown to result from mutations in the p63 gene. These syndromes have various combinations of limb malformations fitting the split hand-split foot spectrum, orofacial clefting, and ectodermal dysplasia. The p63 syndrome family includes the EEC syndrome, AEC syndrome, ADULT syndrome, limb-mammary syndrome, and non-syndromic split hand/foot malformation. The pattern of heterozygous mutations is distinct for each of these syndromes. The functional effects on the p63 proteins also vary between syndromes. In all of these syndromes, the mutation appears to have both dominant negative and gain of function effects rather than causing a simple loss of function.

Congenital Abnormalities↗

Split-hand/split-foot malformation with paternal mutation in the p63 gene.

We report the prenatal diagnosis at 16 weeks' gestation of bilateral split-hand/split-foot malformation (SHSFM) with severe lobster claw deformity of hands and feet in a male fetus without associated malformations. A minor manifestation of SHSFM was present in the father with only mild bilateral foot involvement (syndactyly I-II; cleft II-III; left cutaneous syndactyly III-IV). Mutation analysis of the p63 gene on chromosome 3q27 showed a missense mutation 577A-->G (predicting amino acid substitution K193E) in the father. This mutation has not been reported so far in SHSFM but resembles the previously reported 580A-->G (predicting amino acid substitution K194E) in a family with SHSFM.

Adult↗

Phenotype variations within a choroideremia family lacking the entire CHM gene.

A Swedish family with choroideremia and a deletion of the CHM gene has been studied with ophthalmological examination, full-field electroretinography, and DNA analysis in order to characterize the phenotype of the disease. Although all four patients studied had a complete deletion of the gene, they showed a considerable variability regarding the phenotype, including the electroretinogram tracings. Two of the affected males demonstrated a severe form of choroideremia with low or nondetectable ERG recordings, while the other two affected males showed a less severe phenotype with only a slight reduction of the ERG amplitudes. The variation of the clinical phenotype among family members carrying the same mutation indicates that the severity of choroideremia is not solely a function of the CHM gene.

Adult↗

Cis- and trans-acting elements in cowpea mosaic virus RNA replication.

Cowpea mosaic virus (CPMV) B-RNA encodes the viral proteins required for viral RNA replication while M-RNA does so for the capsid proteins and functions required in cell-to-cell movement of the virus. Accordingly, B-RNA can replicate by itself, whereas M-RNA can only replicate in the presence of B-RNA. We have made heterologous sequence insertions at different positions in the open reading frame of B-RNA, leaving the 5' and 3' non-coding ends intact. None of these mutant B-RNAs were able to replicate. Furthermore, it was not possible to support replication of these mutant B-RNAs by co-inoculating wild-type B-RNA as a helper, indicating that B-RNA can not be replicated in trans. In contrast, replication of M-RNA must occur in trans, as the viral replicative proteins are encoded by B-RNA. Mutant M-RNA transcripts containing 5' and 3' non-coding regions of B-RNA are still efficiently replicated in protoplasts if co-inoculated with B-RNA, indicating that in cis or in trans replication of the CPMV RNAs is not primarily determined by the non-coding regions. Remarkably, for replication of M-RNA, the N-terminal domain of the 58K protein encoded by M-RNA was found to be required.

Base Sequence↗