A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development, or it can be inherited from two parents who are carriers of a faulty gene or from a parent with the disorder. When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA.
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.
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.
Walker–Warburg syndrome (WWS), also called Warburg syndrome, Chemke syndrome, HARD syndrome, Pagon syndrome, cerebroocular dysgenesis (COD) or cerebroocular dysplasia-muscular dystrophy syndrome (COD-MD), is a rare form of autosomal recessive congenital muscular dystrophy. It is associated with brain and eye abnormalities. This condition has a worldwide distribution. Walker-Warburg syndrome is estimated to affect 1 in 60,500 newborns worldwide.
Autosomal recessive multiple epiphyseal dysplasia (ARMED), also called epiphyseal dysplasia, multiple, 4 (EDM4), multiple epiphyseal dysplasia with clubfoot or –with bilayered patellae, is an autosomal recessive congenital disorder affecting cartilage and bone development. The disorder has relatively mild signs and symptoms, including joint pain, scoliosis, and malformations of the hands, feet, and knees.
Oculocerebrorenal syndrome is a rare X-linked recessive disorder characterized by congenital cataracts, hypotonia, intellectual disability, proximal tubular acidosis, aminoaciduria and low-molecular-weight proteinuria. Lowe syndrome can be considered a cause of Fanconi syndrome.
Bare lymphocyte syndrome type II is a rare recessive genetic condition in which a group of genes called major histocompatibility complex class II are not expressed. The result is that the immune system is severely compromised and cannot effectively fight infection.
RAPADILINO syndrome is an autosomal recessive disorder characterized by:
Arterial tortuosity syndrome is an extremely rare congenital connective tissue condition disorder characterized by tortuosity, elongation, stenosis, or aneurysms in major and medium-size arteries including the aorta. It is associated with hyperextensible skin and hypermobility of joints, however symptoms vary depending on the person. Because ATS is so rare, relatively little is known about the disease compared to more common diseases.
Björnstad syndrome is an autosomal recessive congenital condition involving pili torti, sensorineural deafness, and hair abnormalities. It was first characterized in 1965, in Oslo, by prof. Roar Theodor Bjørnstad after he observed an association between pili torti and hearing loss. The condition is extremely rare, with less than 50 cases documented in medical literature worldwide.
Nakajo syndrome, also called nodular erythema with digital changes, is a rare autosomal recessive congenital disorder first reported in 1939 by A. Nakajo in the offspring of consanguineous parents. The syndrome can be characterized by erythema, loss of body fat in the upper part of the body, and disproportionately large eyes, ears, nose, lips, and fingers.
Ullrich congenital muscular dystrophy (UCMD) is a form of congenital muscular dystrophy. There are two forms: UCMD1 and UCMD2.
Malpuech facial clefting syndrome, also called Malpuech syndrome or Gypsy type facial clefting syndrome, is a rare congenital syndrome. It is characterized by facial clefting, a caudal appendage, growth deficiency, intellectual and developmental disability, and abnormalities of the renal system (kidneys) and the male genitalia. Abnormalities of the heart, and other skeletal malformations may also be present. The syndrome was initially described by Georges Malpuech and associates in 1983. It is thought to be genetically related to Juberg-Hayward syndrome. Malpuech syndrome has also been considered as part of a spectrum of congenital genetic disorders associated with similar facial, urogenital and skeletal anomalies. Termed "3MC syndrome", this proposed spectrum includes Malpuech, Michels and Mingarelli-Carnevale (OSA) syndromes. Mutations in the COLLEC11 and MASP1 genes are believed to be a cause of these syndromes. The incidence of Malpuech syndrome is unknown. The pattern of inheritance is autosomal recessive, which means a defective (mutated) gene associated with the syndrome is located on an autosome, and the syndrome occurs when two copies of this defective gene are inherited.
Cantú syndrome is a rare condition characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. Less than 50 cases have been described in the literature; they are associated with a mutation in the ABCC9-gene that codes for the ABCC9-protein.
Legius syndrome (LS) is an autosomal dominant condition characterized by cafe au lait spots. It was first described in 2007 and is often mistaken for neurofibromatosis type I. It is caused by mutations in the SPRED1 gene. It is also known as neurofibromatosis type 1-like syndrome.
Cernunnos deficiency is a form of combined immunodeficiency characterized by microcephaly, due to mutations in the NHEJ1 gene, it is inherited via autosomal recessive manner Management for this condition is antiviral prophylaxis and antibiotic treatment
Kenny-Caffey syndrome type 2 (KCS2) is an extremely rare autosomal dominant genetic condition characterized by dwarfism, hypermetropia, microphthalmia, and skeletal abnormalities. This subtype of Kenny-Caffey syndrome is caused by a heterozygous mutation in the FAM111A gene (615292) on chromosome 11q12.
Waardenburg anophthalmia syndrome is a rare autosomal recessive genetic disorder which is characterized by either microphthalmia or anophthalmia, osseous synostosis, ectrodactylism, polydactylism, and syndactylism. So far, 29 cases from families in Brazil, Italy, Turkey, and Lebanon have been reported worldwide. This condition is caused by homozygous mutations in the SMOC1 gene, in chromosome 14.
Holoprosencephaly-ectrodactyly-cleft lip/palate syndrome, also simply known as Hartsfield syndrome, is a rare genetic disorder characterized by the presence of variable holoprosencephaly, ectrodactyly, cleft lip and palate, alongside generalized ectodermal abnormalities. Additional findings include endocrine anomalies and developmental delays.
