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.
Zellweger syndrome is a rare congenital disorder characterized by the reduction or absence of functional peroxisomes in the cells of an individual. It is one of a family of disorders called Zellweger spectrum disorders which are leukodystrophies. Zellweger syndrome is named after Hans Zellweger (1909–1990), a Swiss-American pediatrician, a professor of pediatrics and genetics at the University of Iowa who researched this disorder.
Pendred syndrome is a genetic disorder leading to congenital bilateral sensorineural hearing loss and goitre with euthyroid or mild hypothyroidism. There is no specific treatment, other than supportive measures for the hearing loss and thyroid hormone supplementation in case of hypothyroidism. It is named after Vaughan Pendred (1869–1946), the British doctor who first described the condition in an Irish family living in Durham in 1896. It accounts for 7.5% to 15% of all cases of congenital deafness.
Crouzon syndrome is an autosomal dominant genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial arch, which is the precursor of the maxilla and mandible. Because the branchial arches are important developmental features in a growing embryo, disturbances in their development create lasting and widespread effects. The syndrome is caused by a mutation in a gene on chromosome 10 that controls the body's production of fibroblast growth factor receptor 2 (FGFR2).
Barakat syndrome is a rare disease characterized by hypoparathyroidism, sensorineural deafness and renal disease, and hence also known as HDR syndrome. It is an autosomal dominant condition with incomplete penetrance and variable expressivity that was first described by Amin J. Barakat et al. in 1977.
Peroxisomal disorders represent a class of medical conditions caused by defects in peroxisome functions. This may be due to defects in single enzymes important for peroxisome function or in peroxins, proteins encoded by PEX genes that are critical for normal peroxisome assembly and biogenesis.
D-Bifunctional protein deficiency is an autosomal recessive peroxisomal fatty acid oxidation disorder. Peroxisomal disorders are usually caused by a combination of peroxisomal assembly defects or by deficiencies of specific peroxisomal enzymes. The peroxisome is an organelle in the cell similar to the lysosome that functions to detoxify the cell. Peroxisomes contain many different enzymes, such as catalase, and their main function is to neutralize free radicals and detoxify drugs. For this reason peroxisomes are ubiquitous in the liver and kidney. D-BP deficiency is the most severe peroxisomal disorder, often resembling Zellweger syndrome.
Vici syndrome, also called immunodeficiency with cleft lip/palate, cataract, hypopigmentation and absent corpus callosum, is a rare autosomal recessive congenital disorder characterized by albinism, agenesis of the corpus callosum, cataracts, cardiomyopathy, severe psychomotor retardation, seizures, immunodeficiency and recurrent severe infections. To date, about 50 cases have been reported.
Infantile Refsum disease (IRD) is a rare autosomal recessive congenital peroxisomal biogenesis disorder within the Zellweger spectrum. These are disorders of the peroxisomes that are clinically similar to Zellweger syndrome and associated with mutations in the PEX family of genes. IRD is associated with deficient phytanic acid catabolism, as is adult Refsum disease, but they are different disorders that should not be confused.
Peroxisome biogenesis factor 1, also known as PEX1, is a protein which in humans is encoded by the PEX1 gene.
Peroxisomal biogenesis factor 2 is a protein that in humans is encoded by the PEX2 gene.
Peroxisome assembly protein 12 is a protein that in humans is encoded by the PEX12 gene.
Peroxisome assembly factor 2 is a protein that in humans is encoded by the PEX6 gene. PEX6 is an AAA ATPase that localizes to the peroxisome. PEX6 forms a hexamer with PEX1 and is recruited to the membrane by PEX26.
Peroxisome biogenesis factor 10 is a protein that in humans is encoded by the PEX10 gene. Alternative splicing results in two transcript variants encoding different isoforms.
Peroxisome assembly protein 26 is a protein that in humans is encoded by the PEX26 gene.
Distal 18q- is a genetic condition caused by a deletion of genetic material within one of the two copies of chromosome 18. The deletion involves the distal section of 18q and typically extends to the tip of the long arm of chromosome 18.
Oculofaciocardiodental syndrome is a rare X-linked dominant genetic disorder.
Zellweger spectrum disorders are a group of rare disorders that create the same disease process. The subdivisions of this spectrum are hyperpipecolic acidemia, infantile Refsum disease, neonatal adrenoleukodystrophy, and Zellweger syndrome. It can also be referred to as peroxisomal biogenesis disorders, Zellweger syndrome spectrum, NALD, cerebrohepatorenal syndrome, and ZSS. It can affect many body organs, including the kidneys, eyes, and hearing. It is named after Hans Zellweger.
Waardenburg syndrome type 1 is a congenital disorder that caused by a mutation in the PAX3 gene that results in abnormal development in the neural crest during early development. Type 1 results in early graying and white forelock and a notable distance between the eyes, noted as dystopia canthorum. Common symptoms of the disease also includes non-progressive hearing loss in majority of patients with type 1. Patients can display complete or partial heterochromia and hypoplastic blue irides and congenital leukemia.
Ocular albinism late onset sensorineural deafness (OASD) is a rare, X-linked recessive disease characterized by intense visual impairments, reduced retinal pigments, translucent pale-blue irises and moderately severe hearing loss from adolescence to middle-age. It is a subtype of Ocular Albinism (OA) that is linked to Ocular albinism type I (OA1). OA1 is the most common form of ocular albinism, affecting at least 1/60,000 males.
