Johanson-Blizzard syndrome with mild phenotypic features confirmed by UBR1 gene testing

Johanson-Blizzard syndrome (JBS) is a rare autosomal recessive condition associated with exocrine pancreatic insufficiency, and is characterized by hypoplastic nasal alae, mental retardation, sensorineural hearing loss, short stature, scalp defects, dental abnormalities and abnormal hair patterns. Growth hormone deficiency, hypopituitarism, and impaired glucagon secretion response to insulin-induced hypoglycemia have been reported. Congenital heart defects have also been described in this condition. Mental retardation is typically moderate to severe in patients with JBS; however, normal intelligence can occur. In the pancreas, there is a selective defect of acinar tissue, whereas the islets of Langerhans and ducts are preserved. Diabetes has been reported in older children, suggesting the progressive nature of pancreatic disease. The molecular basis of JBS has recently been mapped to chromosome 15q15-q21 with identified mutations in the UBR1 gene. We report the case of a 7-year-old female with pancreatic insufficiency and mild phenotypic features, in whom the diagnosis of JBS was established using recently described molecular testing for the UBR1 gene

Johanson-Blizzard syndrome with mild phenotypic features

doi:10.3748/wjg.14.686

Evolutionary adaptations of ruminants and their potential relevance for modern production systems

Comparative physiology applies methods established in domestic animal science to a wider variety of species. This can lead to improved insight into evolutionary adaptations of domestic animals, by putting domestic species into a broader context. Examples include the variety of responses to seasonally fluctuating environments, different adaptations to heat and drought, and in particular adaptations to herbivory and various herbivore niches. Herbivores generally face the challenge that a high food intake compromises digestive efficiency (by reducing ingesta retention time and time available for selective feeding and for food comminution), and a variety of digestive strategies have evolved in response. Ruminants are very successful herbivores. They benefit from potential advantages of a forestomach without being constrained in their food intake as much as other foregut fermenters, because of their peculiar reticuloruminal sorting mechanism that retains food requiring further digestion but clears the forestomach of already digested material; the same mechanism also optimises food comminution. Wild ruminants vary widely in the degree to which their rumen contents ‘stratify’, with little stratification in ‘moose-type’ ruminants (which are mostly restricted to a browse niche) and a high degree of stratification into gas, particle and fluid layers in ‘cattle-type’ ruminants (which are more flexible as intermediate feeders and grazers). Yet all ruminants uniformly achieve efficient selective particle retention, suggesting that functions other than particle retention played an important role in the evolution of stratification-enhancing adaptations. One interesting emerging hypothesis is that the high fluid turnover observed in ‘cattle-type’ ruminants – which is a prerequisite for stratification – is an adaptation that not only leads to a shift of the sorting mechanism from the reticulum to the whole reticulorumen, but also optimises the harvest of microbial protein from the forestomach. Although potential benefits of this adaptation have not been quantified, the evidence for convergent evolution toward stratification suggests that they must be substantial. In modern production systems, the main way in which humans influence the efficiency of energy uptake is by manipulating diet quality. Selective breeding for conversion efficiency has resulted in notable differences between wild and domestic animals. With increased knowledge on the relevance of individual factors, that is fluid throughput through the reticulo-rumen, more specific selection parameters for breeding could be defined to increase productivity of domestic ruminants by continuing certain evolutionary trajectories