Successful DNA-based prenatal diagnosis of the 728+1 g→t mutation at the exon 6-intron 6 junction in the carbonic anhydrase II gene
✍ Scribed by M. Rafiq Islam; Pietro Strisciuglio; Giuseppe Bonapace; William S. Sly
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 146 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0197-3851
No coin nor oath required. For personal study only.
✦ Synopsis
and three siblings (aged 17, 20 and 22 years) also had an elongated chromosome 16 short arm. During counselling, the parents were informed of the familial nature of the anomaly. They were informed that the cytogenetic characterization of the chromosome 16 anomaly and the information derived from previous similar reports suggested favourable prognosis. The couple elected to continue the pregnancy. A healthy girl and boy were delivered at term and their physical and psycho-motor developments are normal at the age of two years and six months.
A review of the literature as well as our report supports the hypothesis of the existence of 'silent' euchromatic duplications involving the proximal short arm of chromosome 16. In our report RHG-banding was in favour of a duplication of the proximal 16p region. It is entirely possible that the partial trisomy 16, apparently without phenotypical consequences, reported by Paoloni-Giacobino et al. (1988) corresponds to the 16p region implicated in our duplication and in those previously reported in the literature.
The propositus with the supernumerary r( 16) shows no developmental delay at the age of 10 months. However, it is noteworthy that longer follow-up will be necessary to definitely conclude to the inocuity of this excess of chromosome 16 material. We agree with the authors that it will be interesting to identify the loci present in the ring chromosome. In the future, molecular investigation of the DNA region involved in the supernumerary r( 16) chromosome and the regions involved in the chromosome 16 short arm duplications of phenotypically normal patients will provide insight into the underlying mechanisms of 'silent' euchromatic duplications.