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.
Ichthyosis vulgaris is a skin disorder causing dry, scaly skin. It is the most common form, and one of the mildest forms, of ichthyosis, affecting around 1 in 250 people. For this reason it is known as common ichthyosis. It is usually an autosomal dominant inherited disease, although a rare non-heritable version called acquired ichthyosis exists.
Lamellar ichthyosis, also known as ichthyosis lamellaris and nonbullous congenital ichthyosis, is a rare inherited skin disorder, affecting around 1 in 600,000 people.
Keratosis pilaris is a common, autosomal-dominant, genetic condition of the skin's hair follicles characterized by the appearance of possibly itchy, small, gooseflesh-like bumps, with varying degrees of reddening or inflammation. It most often appears on the outer sides of the upper arms, thighs, face, back, and buttocks; KP can also occur on the hands, and tops of legs, sides, or any body part except glabrous (hairless) skin. Often the lesions can appear on the face, which may be mistaken for acne or folliculitis.
X-linked ichthyosis is a skin condition caused by the hereditary deficiency of the steroid sulfatase (STS) enzyme that affects 1 in 2000 to 1 in 6000 males. XLI manifests with dry, scaly skin and is due to deletions or mutations in the STS gene. XLI can also occur in the context of larger deletions causing contiguous gene syndromes. Treatment is largely aimed at alleviating the skin symptoms. The term is from the Ancient Greek 'ichthys' meaning 'fish'.
Meleda disease (MDM) or "mal de Meleda", also called Mljet disease, keratosis palmoplantaris and transgradiens of Siemens, is an extremely rare autosomal recessive congenital skin disorder in which dry, thick patches of skin develop on the soles of the hands and feet, a condition known as palmoplantar hyperkeratosis. Meleda Disease is a skin condition which usually can be identified not long after birth. This is a genetic condition but it is very rare. The hands and feet usually are the first to show signs of the disease but the disease can advance to other parts of the body. Signs of the disease include thickening of the skin, on hands and soles of feet, which can turn red in color. There currently is no cure and treatment is limited, but Acitretin can be used in severe cases.
SCARF syndrome is a rare syndrome characterized by skeletal abnormalities, cutis laxa, craniostenosis, ambiguous genitalia, psychomotor retardation, and facial abnormalities. These characteristics are what make up the acronym SCARF. It shares some features with Lenz-Majewski hyperostotic dwarfism. It is a very rare disease with an incidence rate of approximately one in a million newborns. It has been clinically described in two males who were maternal cousins, as well as a 3-month-old female. Babies affected by this syndrome tend to have very loose skin, giving them an elderly facial appearance. Possible complications include dyspnea, abdominal hernia, heart disorders, joint disorders, and dislocations of multiple joints. It is believed that this disease's inheritance is X-linked recessive.
Sjögren–Larsson syndrome is a rare autosomal recessive form of ichthyosis with neurological symptoms. It can be identified by a triad of medical disorders. The first is ichthyosis, which is a buildup of skin to form a scale-like covering that causes dry skin and other problems. The second identifier is paraplegia which is characterized by leg spasms. The final identifier is intellectual delay.
Dermatopathia pigmentosa reticularis(DPR) is a rare, autosomal dominant congenital disorder that is a form of ectodermal dysplasia. Dermatopathia pigmentosa reticularis is composed of the triad of generalized reticulate hyperpigmentation, noncicatricial alopecia, and onychodystrophy. DPR is a non life-threatening disease that largely affects the skin, hair, and nails. It has also been identified as a keratin disorder. Historically, as of 1992, only 10 cases had been described in world literature; however, due to recent advances in genetic analysis, five additional families studied in 2006 have been added to the short list of confirmed cases.
Genodermatosis is a hereditary skin disease with three inherited modes including single gene inheritance, multiple gene inheritance and chromosome inheritance. There are many different types of genodermatosis, the prevalence of genodermatosis ranges from 1 per 6000 people to 1 per 500,000 people. Genodermatosis has influence on the texture, color and structure of skin cuticle and connective tissue, specific lesion site and clinical manifestations on the body vary depending on the type. In the spite of the variety and complexity of genodermatosis, there are still some common methods that can help people diagnose. After diagnosis, different types of genodermatosis require different levels of therapy including interventions, nursing interventions and treatments. Among that, research of therapy for some new, complex and rare types are still in the developing stage. The impact of genodermatosis not only can be seen in body but also can be seen in all aspects of patients' life, including but not limited to psychological, family life, economic conditions and social activities. Accordingly, the patients need treatment, support and help in these areas.
Ichthyosis bullosa of Siemens is a type of familial, autosomal dominant ichthyosis, a rare skin disorder. It is also known as bullous congenital ichthyosiform erythroderma of Siemens or ichthyosis exfoliativa. It is a genetic disorder with no known cure which is estimated to affect about 1 in 500,000 people.
Congenital ichthyosiform erythroderma, also known as nonbullous congenital ichthyosiform erythroderma, is a rare type of the ichthyosis family of skin diseases which occurs in 1 in 200,000 to 300,000 births. The disease comes under the umbrella term autosomal recessive congenital ichthyosis, which include non-syndromic congenital ichthyoses such as harlequin ichthyosis and lamellar ichthyosis.
IFAP syndrome is an extremely rare genetic syndrome. It is also known as Ichthyosis follicularis, alopecia, and photophobia syndrome or simply ichthyosis follicularis. It is extremely rare: there were only 40 known cases until 2011.
Neutral lipid storage disease is a congenital autosomal recessive disorder characterized by accumulation of triglycerides in the cytoplasm of leukocytes, muscle, liver, fibroblasts, and other tissues. It commonly occurs as one of two subtypes, cardiomyopathic neutral lipid storage disease (NLSD-M), or ichthyotic neutral lipid storage disease (NLSD-I) which is also known as Chanarin–Dorfman syndrome), which are characterized primarily by myopathy and ichthyosis, respectively. Normally, the ichthyosis that is present is typically non-bullous congenital ichthyosiform erythroderma which appears as white scaling.
Ichthyosis hystrix is a group of rare skin disorders in the ichthyosis family of skin disorders characterized by massive hyperkeratosis with an appearance like spiny scales. This term is also used to refer to a type of epidermal nevi with extensive bilateral distribution.
Trichorrhexis invaginata is a distinctive hair shaft abnormality that may occur sporadically, either in normal hair or with other hair shaft abnormalities, or regularly as a marker for Netherton syndrome. The primary defect appears to be abnormal keratinization of the hair shaft in the keratogenous zone, allowing for intussusception of the fully keratinized and hard distal shaft into the incompletely keratinized and soft proximal portion of the shaft.
Trichothiodystrophy (TTD) is an autosomal recessive inherited disorder characterised by brittle hair and intellectual impairment. The word breaks down into tricho – "hair", thio – "sulphur", and dystrophy – "wasting away" or literally "bad nourishment". TTD is associated with a range of symptoms connected with organs of the ectoderm and neuroectoderm. TTD may be subclassified into four syndromes: Approximately half of all patients with trichothiodystrophy have photosensitivity, which divides the classification into syndromes with or without photosensitivity; BIDS and PBIDS, and IBIDS and PIBIDS. Modern covering usage is TTD-P (photosensitive), and TTD.
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.
Ichthyosis prematurity syndrome (IPS) is a dermatological disease with known genetic causes. This syndrome is a rare subcategory of autosomal recessive congenital ichthyosis (ARCI). It is associated with complications in the mid-trimester of a pregnancy leading to premature births. Although most prevalent in individuals of Scandinavian origin, there have also been scattered cases in people of Japanese, Italian and Indian ethnicity. This disorder is also referred to as ichthyosis congenital type IV.
Nipa‐Like Domain‐Containing 4, also known as NIPAL4 or Ichthyin, is a gene that is predicted to code for a transmembrane protein with nine transmembrane domains. NIPAL4 codes for the protein magnesium transporter NIPA4, which acts as a Mg2+
transporter.
