Tietz syndrome is a disorder characterized by profound hearing loss from birth, fair skin, and light-colored hair. The hearing loss in affected individuals is caused by abnormalities of the inner ear (sensorineural hearing loss) and is present from b READ MORE

Timothy syndrome is a rare disorder that primarily affects the heart but can affect many other areas of the body. The severity of this condition varies among affected individuals, although it is often life-threatening. Timothy syndrome is characteriz READ MORE

TK2 -related mitochondrial DNA depletion syndrome, myopathic form ( TK2 -MDS) is an inherited condition that causes progressive muscle weakness (myopathy). The signs and symptoms of TK2 -MDS typically begin in early childhood. Development is usually READ MORE

Tourette syndrome is a complex disorder characterized by repetitive, sudden, and involuntary movements or noises called tics. Tics usually appear in childhood, and their severity varies over time. In most cases, tics become milder and less frequent i READ MORE

Townes-Brocks syndrome is a genetic condition that affects several parts of the body. The most common features of this condition are a malformation of the anal opening (imperforate anus), abnormally shaped ears, and hand malformations that most often READ MORE

Transcobalamin deficiency is a disorder that impairs the transport of cobalamin (also known as vitamin B12) within the body. Cobalamin is obtained from the diet; this vitamin is found in animal products such as meat, eggs, and shellfish. An inability READ MORE

Transthyretin amyloidosis is a progressive condition characterized by the buildup of abnormal protein deposits called amyloids (amyloidosis) in the body's organs and tissues. These protein deposits most frequently occur in the peripheral nervous syst READ MORE

Treacher Collins syndrome is a condition that affects the development of bones and other tissues of the face. The signs and symptoms of this disorder vary greatly, ranging from almost unnoticeable to severe. Most affected individuals have underdevelo READ MORE

Trichohepatoenteric syndrome is a condition that affects the hair (tricho-), liver (hepato-), and intestines (enteric), as well as other tissues and organs in the body. This condition is also known as syndromic diarrhea because chronic, difficult-to- READ MORE

Trichorhinophalangeal syndrome type I (TRPS I) is a condition that causes bone and joint malformations; distinctive facial features; and abnormalities of the skin, hair, teeth, sweat glands, and nails. The name of the condition describes some of the READ MORE

Trichorhinophalangeal syndrome type II (TRPS II) is a condition that causes bone and joint malformations; distinctive facial features; intellectual disability; and abnormalities of the skin, hair, teeth, sweat glands, and nails. The name of the condi READ MORE

Trichothiodystrophy, commonly called TTD, is a rare inherited condition that affects many parts of the body. The hallmark of this condition is hair that is sparse and easily broken. In people with trichothiodystrophy, tests show that the hair is lack READ MORE