Trisomy 17 in a bonobo (Pan paniscus) and deletion of 3q in a lowland gorilla (Gorilla gorilla gorilla): comparison with human trisomy 18 and human deletion 4q syndrome

Identification of Chromosome 17 Trisomy in a Cynomolgus Monkey (Macaca fascicularis) by Multicolor FISH Techniques

A female cynomolgus monkey (Macaca fascicularis) with facial features characteristic of Down syndrome showed abnormal behavior, unwariness toward humans, and poor concentration. The number of metaphase chromosomes in blood lymphocytes was examined and found to be 43, which indicated one extra chromosome to the normal diploid number (2n = 42). We then used Q-banding and multicolor FISH techniques to identify the extra chromosome. The results revealed an additional chromosome 17, with no other chromosomal rearrangements, such as translocations. Since no mosaicism or heterozygous variant chromosomes were observed, full trisomy 17 was assessed in this female cynomolgus monkey. Chromosome 17 corresponds to human chromosome 13, and human trisomy 13, known as Patau syndrome, results in severe clinical signs and, often, a short life span; however, this individual has reached an age of 10 years with only mild clinical signs. Although genomic differences exist between human and macaques, this individual's case could help to reveal the pathological and genetic mechanisms of Patau syndrome.

Resources for functional genomic studies of health and development in nonhuman primates

Primates display a wide range of phenotypic variation underlaid by complex genetically regulated mechanisms. The links among DNA sequence, gene function, and phenotype have been of interest from an evolutionary perspective, to understand functional genome evolution and its phenotypic consequences, and from a biomedical perspective to understand the shared and human-specific roots of health and disease. Progress in methods for characterizing genetic, transcriptomic, and DNA methylation (DNAm) variation is driving the rapid development of extensive omics resources, which are now increasingly available from humans as well as a growing number of nonhuman primates (NHPs). The fast growth of large-scale genomic data is driving the emergence of integrated tools and databases, thus facilitating studies of gene functionality across primates. This review describes NHP genomic resources that can aid in exploration of how genes shape primate phenotypes. It focuses on the gene expression trajectories across development in different tissues, the identification of functional genetic variation (including variants deleterious for protein function and regulatory variants modulating gene expression), and DNAm profiles as an emerging tool to understand the process of aging. These resources enable comparative functional genomics approaches to identify species-specific and primate-shared gene functionalities associated with health and development.

A SYSTEMATIC REVIEW OF THE LITERATURE RELATING TO CAPTIVE GREAT APE MORBIDITY AND MORTALITY

Wild bonobos (Pan paniscus), chimpanzees (Pan troglodytes), Western gorillas (Gorilla gorilla), and orangutans (Pongo pygmaeus, Pongo abelii) are threatened with extinction. In order to help maintain a self-sustaining zoo population, clinicians require a sound understanding of the diseases with which they might be presented. To provide an up-to-date perspective on great ape morbidity and mortality, a systematic review of the zoological and veterinary literature of great apes from 1990 to 2014 was conducted. This is the first review of the great ape literature published since 1990 and the first-ever systematic literature review of great ape morbidity and mortality. The following databases were searched for relevant articles: CAB Abstracts, Web of Science Core Collection, BIOSIS Citation Index, BIOSIS Previews, Current Contents Connect, Data Citation Index, Derwent Innovations Index, MEDLINE, SciELO Citation Index, and Zoological Record. A total of 189 articles reporting on the causes of morbidity and mortality among captive great apes were selected and divided into comparative morbidity-mortality studies and case reports-series or single-disease prevalence studies. The content and main findings of the morbidity-mortality studies were reviewed and the main limitations identified. The case reports-case series and single-disease prevalence studies were categorized and coded according to taxa, etiology, and body system. Subsequent analysis allowed the amount of literature coverage afforded to each category to be calculated and the main diseases and disorders reported within the literature to be identified. This review concludes that reports of idiopathic and infectious diseases along with disorders of the cardiovascular, respiratory, and gastrointestinal body systems were particularly prominent within the great ape literature during 1990-2014. However, recent and accurate prevalence figures are lacking and there are flaws in those reviews that do exist. There is therefore a critical need for a robust, widespread, and more up-to-date review of mortality among captive great apes.

Unusual Turner syndrome mosaic with a triple x cell line (47,X/49,XXX) in a western lowland gorilla (Gorilla gorilla gorilla)

A 29-yr-old female western lowland gorilla (Gorilla gorilla gorilla) was evaluated for low fertility and a midterm abortion. Laboratory testing included karyotyping, which revealed an unusual mosaicism for Turner syndrome with Triple X (47,X/49,XXX). This appears to be the first report of Turner syndrome in a great ape. In humans, Turner syndrome occurs in approximately 1 in 3,000 females, with half of those monosomic for the X chromosome. A small proportion is mosaic for a triple X cell line (3-4%). In humans, Turner syndrome is associated with characteristic phenotype including short stature, obesity, a broad chest with widely spaced nipples, webbing of the neck, and anteverted ears. This individual gorilla is significantly shorter in stature than conspecifics and is obese despite normal caloric intake. Individuals with Turner syndrome should also be screened for common health issues, including congenital heart defects, obesity, kidney abnormalities, hypertension, hypothyroidism, and diabetes mellitus. Animals with decreased fertility, multiple miscarriages, fetal losses, unusual phenotypes, or a combination of these symptoms should be evaluated for genetic abnormalities.

Identification of differences in human and great ape phytanic acid metabolism that could influence gene expression profiles and physiological functions

Background

It has been proposed that anatomical differences in human and great ape guts arose in response to species-specific diets and energy demands. To investigate functional genomic consequences of these differences, we compared their physiological levels of phytanic acid, a branched chain fatty acid that can be derived from the microbial degradation of chlorophyll in ruminant guts. Humans who accumulate large stores of phytanic acid commonly develop cerebellar ataxia, peripheral polyneuropathy, and retinitis pigmentosa in addition to other medical conditions. Furthermore, phytanic acid is an activator of the PPAR-alpha transcription factor that influences the expression of genes relevant to lipid metabolism.

Results

Despite their trace dietary phytanic acid intake, all great ape species had elevated red blood cell (RBC) phytanic acid levels relative to humans on diverse diets. Unlike humans, chimpanzees showed sexual dimorphism in RBC phytanic acid levels, which were higher in males relative to females. Cultured skin fibroblasts from all species had a robust capacity to degrade phytanic acid. We provide indirect evidence that great apes, in contrast to humans, derive significant amounts of phytanic acid from the hindgut fermentation of plant materials. This would represent a novel reduction of metabolic activity in humans relative to the great apes.

Conclusion

We identified differences in the physiological levels of phytanic acid in humans and great apes and propose this is causally related to their gut anatomies and microbiomes. Phytanic acid levels could contribute to cross-species and sex-specific differences in human and great ape transcriptomes, especially those related to lipid metabolism. Based on the medical conditions caused by phytanic acid accumulation, we suggest that differences in phytanic acid metabolism could influence the functions of human and great ape nervous, cardiovascular, and skeletal systems.

Cytogenetics of wild and captive bred non-domestic animals

Cytogenetics of wild and captive bred non-domestic animals provides us with valuable information that can be implemented in wildlife management and species conservation strategies. In this review, we summarized the data published to date describing a range of chromosome abnormalities observed in non-domestic animals and their effect on phenotype. Two important factors that can potentially have drastic effects on captive breeding programs are discussed: presence of classic chromosome abnormalities, spontaneously-occurring and inherited, and intraspecific variations in chromosome number. Short-term consequences, primarily reduced reproductive efficiency, and long-term consequences, such as changes in population dynamics, are examined.

Identification of 2.3-Mb Gene Locus for Congenital Aural Atresia in 18q22.3 Deletion

OBJECTIVE

18q deletion syndrome is a multiple-anomaly mental retardation syndrome associated with congenital aural atresia. The purpose of this study was to determine the frequency of the congenital aural atresia phenotype in 18q deletion syndrome patients and to delineate a potential critical region for congenital aural atresia at the 18q22.3-18q23 region.

STUDY DESIGN AND PATIENTS

The study describes one 18q deletion syndrome clinical report (Patient 15) with an overview of 19 other selected 18q deletion syndrome patients presenting congenital aural atresia from 18 published articles and one presented poster on 18q deletion syndrome.

RESULTS

Our investigation, together with the results of published 18q deletion syndrome reports, shows that the average frequency of congenital aural atresia is approximately 52%. A combination of three 18q deletion syndrome probands defines a chromosomal deletion site for congenital aural atresia at 18q22.3-18q23 in the region between markers D18S489 and D18S554. These polymorphic markers outline a putative critical interval of approximately 2.3 Mb, including the genes ZNF407, ZADH2, SDCCAG33, ZNF516, FLJ44881, ZNF236, MBP-Golli, and GALR1. The haploinsufficiency of these genes is suggested to be a primary cause of congenital aural atresia phenotype in 18q deletion syndrome individuals.

CONCLUSION

Congenital aural atresia is a relevant diagnostic clue and a major recognizable feature of 18q deletion syndrome. Early diagnosis of 18q deletion syndrome may enable application of hearing aids. Knockout studies on the congenital aural atresia mouse gene homolog may add further insight into the genes responsible for this condition.

Trisomy of chromosome 18 in the baboon (Papio hamadryas anubis)

Trisomy 18 is usually a lethal chromosomal abnormality and is the second most common autosomal trisomy in humans, with an incidence of 1:8000 live births. It is commonly associated with abnormalities of the lower and upper extremities, having the frequency of 95% and 65%, respectively. A newborn female olive baboon (Papio hamadryas anubis) was diagnosed with intrauterine growth retardation and severe arthrogryposis-like congenital joint deformities. Cytogenetic analysis including G-banding and fluorescence in situ hybridization (FISH) revealed that the congenital abnormalities were associated with chromosomal mosaicism for trisomy 18. Genetic analysis with microsatellites from chromosome 18 confirmed the maternal origin of the extra chromosome 18. This is the first report of trisomy 18 in the baboon, which may be a promising animal model of human disease.