Authors Address Jacobsen Syndrome, Which

¶ … authors address Jacobsen syndrome, which is related to terminal deletion of 11q chromosome, usually occurring do novo. It is a rare congenital disorder. Beckwith-Wiedemann syndrome is also mentioned. Beckwith-Wiedemann syndrome occurs due to duplication of the paternal allele of 11p15. These are pediatric areas of genetic research, demonstrating the ways chromosomal abnormalities are not necessarily genetically inherited, how they evolve de novo, and how they express themselves at birth. Moreover, the article addresses various diagnostic procedures, including a multitude of chromosomal testing methods for identification of the disease in infants.

The article addresses the methods by which the deletion of the genetic material takes place; that is, breaks at the long end at 11q23.3 -- in "expanded CCG-trinucleotide repeats within the folate sensitive fragile site FRA11b," (962). The trinucleotide repeats can cause increased chromosomal instabilities and eventual terminal deletion of 11q. Complex rearrangements of the chromosomes may not always be identifiable using the most routine methods of testing.

Identify the broad goals of the research described in the article.

The primary goal of the research is to encourage routine testing of Jacobsen syndrome via the use of available technologies and procedures including Array-CGH, FISH, and SKY. Conventional chromosomal analysis can usually identify the absence of the 11q and possible presence of Jacobsen syndrome. Secondary goals include pinpointing the breakpoints that occur in the chromosome. Tertiary goals include urging future research into Jacobsen syndrome in order to reveal the specific mechanisms of the genes on chromosome 11 area q.

Explain the genetic concept tested in the study and how it is tested.

The overall genetic concept tested is prenatal and perinatal chromosomal rearrangement. This is a case study experimental research design. The researchers work with an infant male, born premature (born in the 32+5-week of pregnancy) to two healthy parents. The infant was admitted to hospital for respiratory problems and the subsequent clinical examination revealed several symptoms including organ system impairment, facial dysmorphia, and partial agenesis of the corpus callosum. Chromosome analysis was conducted, via culturing. Moreover, the fluorescence in situ hybridization (FISH) method of analysis was also used on fifteen metaphases. Spectral Karyotyping (SKY) analysis, comparative genomic hybridization (CGH), and array CGH were also used during the diagnostic procedures. It was found that the critical region of 11q was lost, confirming Jacobsen syndrome. The researchers also postulate the presence of Beckwith-Wiedemann syndrome due primarily to the fact that the infant in the case study was large in spite of being premature -- he was in the 97th percentile for length and above the 97th percentile for weight. Large size is a primary expressing symptom of Beckwith-Wiedemann syndrome. The authors also used imaging analysis hardware and software, as well as using the patented CpGenome DNA modification kit for further testing.

Explain how the article relates to genetics topics addressed in lecture.

The article relates to a wide range of genetics topics including chromosomal abnormalities, alleles, the use of fluorescence in chromosomal analysis testing, cytogenetic abnormalities, genotypes, phenotypes, karyotypes, and the process of chromosomal rearrangement or deletion de novo.

Explain the significance of the species chosen for use in the study.

The species chosen for use in the study was human; significance does not need to be explained. The authors did need to receive consent from the parents for all diagnostic procedures, which were performed within the ethical guidelines of the Institutional Review Board of the Hannover Medical School.

Explain the most significant conclusions presented in the article.

One of the most significant conclusions presented in the article is that new methods of chromosomal analyses such as array-CGH and single nucleotide polymorphism (SNP) chips can be especially helpful in situations where Jacobsen, Beckwith-Wiedemann, and other congenital syndromes are suspected. However, the authors admit that further research is required to discover the specific genes on 11q, which have been destroyed and subsequently cause the physical and physiological features of Jacobsen syndrome.

Second, this case is unique in that it revealed an unusual inherited chromosomal arrangement. In this case, it was paternal inversion on p15q24. The parental testing in this study is a reminder of the importance of routine parental genetic testing, for the risk factors associated with syndromes like Jacobsen and Beckwith-Wiedemann. It is implied that both parental and prenatal testing might be useful, especially as Beckwith-Wiedemann leads often to terminal illness.