Critical to the accurate diagnosis of human illness is the need to distinguish clinical features that fall within the normal range from those that do not. That distinction is often challenging and not infrequently requires considerable experience at the bedside. It is not surprising that accurate cytogenetic diagnosis is also often a challenge, especially when chromosome study reveals morphologic findings that raise the question of normality. Given the realization that modern human cytogenetics is just over five decades old, it is noteworthy that thorough documentation of normal chromosome var- tion has not yet been accomplished. One key diagnostic consequence of the inability to distinguish a “normal” variation in chromosome structure from a pathologic change is a missed or inaccurate diagnosis. Clinical cytogeneticists have not, however, been idle. Rather, progressive biotechnological advances coupled with virtual completion of the human genome project have yielded increasingly better microscopic resolution of chromosome structure. Witness the progress from the early short condensed chromosomes to the later visualization of chromosomes through banding techniques, hi- resolution analysis in prophase, and more recently to analysis by fluorescent in situ hybridization (FISH).

Human Chromosome Variation: Heteromorphism and Polymorphism was formerly printed under the title “Atlas of Human Chromosome Heteromorphism”. The Atlas has become a standard reference book in most cytogenetic laboratories and is cited as a significant reference in ISCN 2009. This revised version has updated and retained the most useful pictorial sections of the first edition, including the comprehensive review of normal and “not-so-normal” variations of the human karyotype with summaries and extensive reference lists organized by chromosome number. This updated edition features concise background information on chromosome methods and applications, essential information on heteromorphism frequencies in normal and clinical populations as well as new listing and discussions of euchromatic, subtelomeric and FISH variants. The addition of two new sections make this an even more valuable reference than before. A section on common and rare fragile sites includes a short historical discussion, definitions and an extensive table of officially recognized sites that includes the HUGO name, chromosomal location, methods of induction, genes and references to the most recent molecular characterization. A new section on array CGH discusses the clinical challenge of interpreting copy number variations (CNVs) revealed by this newest technology, gives examples of various levels of interpretation and lists the several most common websites used in this interpretation.

This new edition now titled “Human Chromosome Variation: Heteromorphism, Polymorphism and Pathogenesis” provides the reader with an up-to-date overview of microarrays, fragile sites, copy number variations and whole genome sequencing. Greatly expanding the discussion of microarray analysis in the previous edition of the book, are new chapters on microarray and genomic analysis, plus comprehensive tables on the subtle microdeletions and microduplications that are found on each chromosome, including 235 recurring copy number variants that are associated with well-established or emerging chromosomal syndromes. The current edition features concise information on cytogenetic methods and applications, extending these discussions to DNA analysis and genome sequencing. Sections on euchromatin, heterochromatin, FISH pattern, fragile site, copy number, and DNA sequence variation are integrated with actual clinical examples from cytogenetic laboratories and from clinical practice. The principles that allow for the distinction between benign chromosome / DNA variation and pathogenic heteromorphisms / polymorphisms are discussed and include references to the latest organizational guidelines and genomic or population databases. The two previous incarnations of this book: the ‘Atlas of Human Chromosome Heteromorphism’, and ‘Human Chromosome Variation: Heteromorphism and Polymorphism’ have been standard reference works in most cytogenetic laboratories, used by laboratory directors and clinicians all around the world. While widely used sections from the previous edition on cytogenetic technologies and heteromorphisms are retained intact the present volume adds extensive material on copy number variations (polymorphisms detected by microarray analysis), fragile sites in disease and cancer, and practical views on interpreting emerging technologies, including whole exome sequencing. This book should be of interest to clinicians, technicians and students who are or will be exposed to DNA and/or chromosome analysis and the data derived from these continuously developing techniques. This fully updated book volume will bring the reader up to speed on the latest technologies, their applications, benefits and drawbacks and as such, is a must read for anyone with an interest in DNA and chromosome analysis and the distinction between benign variation and pathogenic mistakes.

This atlas presents the results of cases of structural chromosome aberrations based on the currently available methods of analysis for different types of abnormality. It particularly focuses on which spectrum should be chosen when combining the different techniques to achieve the best method of diagnosis in individual cases, for example direct preparation of cells and mitoses, short or long-time cell culture, fluorescence in situ hybridization (FISH), analysis of interphases, microarray or DNA sequencing. Generally it has to be taken into account, that the development of new and improved investigation methods is forthcoming. Thus, by improvement of diagnostic possibilities new fields of investigation arise, and special groups of patients with cytogenetic analyses can be re-analysed under new research questions.

A stunning visual collection of the banded metaphase chromosomekaryotypes from some 850 species of mammals, the Atlas of MammalianChromosomes represents an unabridged compendium of the state ofthis genomic art form. Bringing together information currentlyscattered throughout the cytogenetics literature for scores ofpublished and unpublished species, this atlas features high-qualitykaryotype images for nearly every mammal studied to date, making itthe most comprehensive assemblage of high-resolution chromosomephotographs available--a critically invaluable resource for today'scomparative genomics era. For every available species, the Atlas of Mammalian Chromosomespresents the best karyotype produced, the common and Latin name ofthe species, the published citation, and the contributing authors.Most karyotypes are G-banded, revealing the chromosomal bar codesof homologous segments among related species. Addressing the mandate of the Human Genome Project to annotate thegenomes of other organisms as well, the Atlas of MammalianChromosomes offers a step forward in our understanding of speciesformation, of genome organization, and of DNA script for naturalselection. It is an invaluable resource for geneticists,mammalogists, and biologists interested in comparative genomics,systematics, and chromosome structure.

Heteromorphisms are microscopically visible variant regions on chromosomes and are transmitted as Mendelian traits. Studies of heteromorphic variants allow determination of parental origin, paternity testing, maternal contamination in prenatal samples or tracing the chromosome to a parent in numerical or structural chromosomal abnormalities. Genetic counseling is important to interpret these common variants in context to patient history as they may have no consequences to mild to moderate consequences. This work presents the study and clinical correlation of common heteromorphic variations in 6166 individuals with bad obstetric history, developmental delay, fetal studies (fetal cells in amniotic fluid or product of conception) with appropriate controls. A review of published literature on the subject is also included. This work was also presented by the author as a doctoral dissertation (PhD in Life sciences) at Mumbai University India in 2012