15q Duplication Syndrome: Report on the First Patient from Ecuador with an Unusual Clinical Presentation

Background. The 15q11.1-13.1 duplication, also known as Dup15q syndrome, is a rare congenital disease affecting 1 in 30,000 to 1 in 60,000 children worldwide. This condition is characterized by the presence of at least one extra copy of genetical material within the Prader-Willi/Angelman Critical Region (PWACR) of the referred 15q11.2-q13.1 chromosome. Case Report. Our study presents the clinical and genetical features of the first patient with a denovo 15q11.2 interstitial duplication on the maternal allele (inv Dup15q) that mimics a milder Prader-Willi syndrome probably due to an atypical disruption of the SNHG14 gene. Methylation-specific MLPA analysis has confirmed the presence of a very unlikely duplication that lies between breakpoint 1 (BP1) and the middle of BP2 and BP3 (BP3). This atypical alteration might be linked to the milder patient’s clinical phenotype. Conclusions. This is the first Dup15q patient reported in Ecuador and of the very few in South America. This aberration has never been described in a patient with Dup15q, and the unusual clinical presentation is probably due to the atypical distal breakpoint occurring within the gene SNHG14 which lies between BP2 and BP3 and does not therefore contain the whole PWACR. If the duplication disrupted the gene, then it is possible that it is the cause of, or contributing to, the patient’s clinical phenotype.

The Behaviour of Bulls at Artificial Insemination Centres

The very wide field of animal behaviour has no more fascinating application than in the bull stud of any artificial insemination centre where the male is subjected to close observation over a long period of time. After a year or two's experience one becomes aware of the qualifications expected of a bull if he is to become a successful A.I. sire. His general temperament must be good, he must be placid and easy to handle, be free from all vices, and be able to produce high quality semen as and when required, and at the same time he must possess superior genetical material so that there is hope of improved production from his progeny.

Experiments on the inactivation of bacteriophage by radiations, and their bearing on the nature of bacteriophage

Three bacteriophages (S-13, C-36 and Staph-K) were irradiated by γ -rays, X -rays and α -rays. The survival curves were exponential, and the effect of a given dose was independent of the exposure time. For any given phage the inactivation doses of the three radiations increased in the order γ -rays, X -rays, α -rays, while for any given radiation the inactivation doses of the three phages diminished in the order S-13, C-36, Staph-K, which is the order of increasing size. These observations lead to the conclusion that a single ionization suffices to inactivate a phage particle. In the case of the smallest phage investigated (S-13) this ionization is effective wherever in the particle it is produced, and reasons are given for concluding from this fact that S-13 is a macromolecular type of virus analogous to the crystallizable plant viruses. In the case of the larger phages (C-36 and Staph-K ), while a single ionization can in­ activate a phage particle it is not sufficient for it to be produced anywhere in the phage particle; to be effective it must be produced in a more restricted region. It is suggested that this radiosensitive region constitutes the genetical material of the phage, and on the basis of this differentiation into genetic and non-genetic material these phages are regarded as primitive single-celled organisms rather than macromolecules.

XVI.—Cytogenetical Analysis of the Chromosomes in the Pig

Now that it is accepted that the phenomena observed in genetical experimentation are repercussions of events which have occurred previously in the chromosomes, it is the rule confidently to appeal, whenever possible, to the evidence derived from cytological studies for final explanations of genetical behaviour. This being so, it follows that in those instances in which, for any reason, experimental breeding work is difficult, studies of the chromosomes during the division cycles may be expected to yield significant information concerning the peculiarities of hereditary transmission that might be expected were such genetical investigation undertaken. Further, the larger mammals of economic importance are, under present conditions, unsatisfactory genetical material; they are expensive, and commonly the details of structure and function which they present for examination are not easily or precisely definable and seem to obey no simple rule of inheritance. For these reasons it seems desirable that thorough cytological studies of these forms should be undertaken, for at least these are not costly and they may be expected to provide explanations of the apparently complicated genetic behaviour which these forms exhibit.