Tietz syndrome, also called Tietz albinism-deafness syndrome or albinism and deafness of Tietz, is an autosomal dominant congenital disorder characterized by deafness and leucism. It is caused by a mutation in the microphthalmia-associated transcription factor (MITF) gene. Tietz syndrome was first described in 1963 by Walter Tietz (1927–2003) a German Physician working in California.
Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes, a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities.
Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.
Norrie disease is a rare disease and genetic disorder that primarily affects the eyes and almost always leads to blindness. It is caused by mutations in the Norrin cystine knot growth factor (NDP) gene, which is located on the X chromosome. In addition to the congenital ocular symptoms, the majority of patients experience a progressive hearing loss starting mostly in their 2nd decade of life, and some may have learning difficulties among other additional characteristics.
Neuronal ceroid lipofuscinosis is the general name for a family of at least eight genetically separate neurodegenerative lysosomal storage diseases that result from excessive accumulation of lipopigments (lipofuscin) in the body's tissues. These lipopigments are made up of fats and proteins. Their name comes from the word stem "lipo-", which is a variation on lipid, and from the term "pigment", used because the substances take on a greenish-yellow color when viewed under an ultraviolet light microscope. These lipofuscin materials build up in neuronal cells and many organs, including the liver, spleen, myocardium, and kidneys.
Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics.
Preimplantation genetic haplotyping (PGH) is a clinical method of preimplantation genetic diagnosis (PGD) used to determine the presence of single gene disorders in offspring. PGH provides a more feasible method of gene location than whole-genome association experiments, which are expensive and time-consuming.
Ranajit Chakraborty was a human and population geneticist. At the time of his death, he was Director of the Center for Computational Genomics at the Institute of Applied Genetics and Professor in the Department of Forensic and Investigative Genetics at the University of North Texas Health Science Center in Fort Worth, Texas. His scientific contributions include studies in human genetics, population genetics, genetic epidemiology, statistical genetics, and forensic genetics.
Jan Gunnar Faye Mohr was a Norwegian-Danish physician and geneticist, known for his discovery of the first cases of autosomal genetic linkage in man, between the Lutheran blood groups and the ABH-secretor system, and between these and the hereditary disease myotonic dystrophy. Besides being first steps in mapping the human genome, the findings illustrated the medical potential of linkage analysis in prenatal genetic diagnosis. Mohr is eponymously known by the syndrome Mohr-Tranebjærg, a progressive deafness with X-linked mode of inheritance, which was first described by Jan Mohr, and then more comprehensively by Tranebjærg et al. The 'Mohr syndrome', or oral-facial-digital syndrome type II, is named after Otto Lous Mohr, uncle of Jan Mohr.
P protein, also known as melanocyte-specific transporter protein or pink-eyed dilution protein homolog, is a protein that in humans is encoded by the oculocutaneous albinism II (OCA2) gene. The P protein is believed to be an integral membrane protein involved in small molecule transport, specifically of tyrosine—a precursor of melanin. Certain mutations in OCA2 result in type 2 oculocutaneous albinism. OCA2 encodes the human homologue of the mouse p gene.
Cat genetics describes the study of inheritance as it occurs in domestic cats. In feline husbandry it can predict established traits (phenotypes) of the offspring of particular crosses. In medical genetics, cat models are occasionally used to discover the function of homologous human disease genes.
Jansky–Bielschowsky disease is an extremely rare autosomal recessive genetic disorder that is part of the neuronal ceroid lipofuscinosis (NCL) family of neurodegenerative disorders. It is caused by the accumulation of lipopigments in the body due to a deficiency in tripeptidyl peptidase I as a result of a mutation in the TPP1 gene. Symptoms appear between ages 2 and 4 and consist of typical neurodegenerative complications: loss of muscle function (ataxia), drug resistant seizures (epilepsy), apraxia, development of muscle twitches (myoclonus), and vision impairment. This late-infantile form of the disease progresses rapidly once symptoms are onset and ends in death between age 8 and teens. The prevalence of Jansky–Bielschowsky disease is unknown; however, NCL collectively affects an estimated 1 in 100,000 individuals worldwide. Jansky–Bielschowsky disease is related to late-infantile Batten disease and LINCL, and is under the umbrella of neuronal ceroid lipofuscinosis.
A ciliopathy is any genetic disorder that affects the cellular cilia or the cilia anchoring structures, the basal bodies, or ciliary function. Primary cilia are important in guiding the process of development, so abnormal ciliary function while an embryo is developing can lead to a set of malformations that can occur regardless of the particular genetic problem. The similarity of the clinical features of these developmental disorders means that they form a recognizable cluster of syndromes, loosely attributed to abnormal ciliary function and hence called ciliopathies. Regardless of the actual genetic cause, it is clustering of a set of characteristic physiological features which define whether a syndrome is a ciliopathy.
Paul Kjer is a Danish ophthalmologist who studied a condition in nineteen families that was characterized by infantile optic atrophy along with a dominant inheritance mode. In 1959, the condition was named Kjer's optic neuropathy in his honor.
Forkhead box protein E3 (FOXE3) also known as forkhead-related transcription factor 8 (FREAC-8) is a protein that in humans is encoded by the FOXE3 gene located on the short arm of chromosome 1.
Richard Cotton AM was an Australian medical researcher and founder of the Murdoch Institute and the Human Variome Project. Cotton focused on the prevention and treatment of genetic disorders and birth defects.
Blue cone monochromacy (BCM) is an inherited eye disease that causes severe color blindness, poor visual acuity, nystagmus and photophobia due to the absence of functional red (L) and green (M) cone photoreceptor cells in the retina. BCM is a recessive X-linked disease and almost exclusively affects XY karyotypes.
Jean-Louis Mandel, born in Strasbourg on February 12, 1946, is a French medical doctor and geneticist, and heads a research team at the Institute of Genetics and Molecular and Cellular Biology (IGBMC). He has been in charge of the genetic diagnosis laboratory at the University Hospitals of Strasbourg since 1992, as well as a professor at the Collège de France since 2003.
Robert Williamson is a retired British-Australian molecular biologist who specialised in the mapping, gene identification, and diagnosis of human genetic disorders.
Grant Robert Sutherland is a retired Australian human geneticist and celebrated cytogeneticist. He was the Director, Department of Cytogenetics and Molecular Genetics, Adelaide Women's and Children's Hospital for 27 years (1975-2002), then became the Foundation Research Fellow there until 2007. He is an Emeritus Professor in the Departments of Paediatrics and Genetics at the University of Adelaide.
