Brachydactyly is a medical term which literally means 'short finger'. The shortness is relative to the length of other long bones and other parts of the body. Brachydactyly is an inherited, dominant trait. It most often occurs as an isolated dysmelia, but can also occur with other anomalies as part of many congenital syndromes. Brachydactyly may also be a signal that one is at risk for congenital heart disease due to the association between congenital heart disease and carpenter's syndrome and the link between carpenter's syndrome and brachydactyly.
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position, the thumb is the outermost digit. The Medical Latin English noun for thumb is pollex, and the corresponding adjective for thumb is pollical.
The phalanges are digital bones in the hands and feet of most vertebrates. In primates, the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones.
Tyrosine-protein kinase transmembrane receptor ROR2, also known as neurotrophic tyrosine kinase, receptor-related 2, is a protein that in humans is encoded by the ROR2 gene located on position 9 of the long arm of chromosome 9. This protein is responsible for aspects of bone and cartilage growth. It is involved in Robinow syndrome and autosomal dominant brachydactyly type B. ROR2 is a member of the receptor tyrosine kinase-like orphan receptor (ROR) family.
Hitchhiker's thumb, also known as distal hyperextensibility of the thumb, is the condition of having a thumb that has a distal phalange that bends backwards in an angle of 90°. This condition is benign and does not cause pain or affect the thumb with the trait negatively.
A hand is a prehensile, multi-fingered appendage located at the end of the forearm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala are often described as having "hands" instead of paws on their front limbs. The raccoon is usually described as having "hands" though opposable thumbs are lacking.
In racquet nails, the nail plate is flattened, the end of the thumb is widened and flattened, and the distal phalanx is abnormally short. In racquet nails, the width of the nail bed and nail plate is greater than their length. The condition is painless and asymptomatic.
Cooks syndrome is a hereditary disorder which is characterized in the hands by bilateral nail hypoplasia on the thumb, index finger, and middle finger, absence of fingernails (anonychia) on the ring finger and little finger, lengthening of the thumbs, and bulbousness of the fingers. In the feet, it is characterized by absence of toenails and absence/hypoplasia of the distal phalanges. In the second study of this disorder, it was found that the intermediate phalanges, proximal phalanges, and metacarpals were unaffected.
Nicolaides–Baraitser syndrome (NCBRS) is a rare genetic condition caused by de novo missense mutations in the SMARCA2 gene and has only been reported in fewer than 200 cases worldwide. NCBRS is a distinct condition and well recognizable once the symptoms have been identified.
Hand-foot-genital syndrome (HFGS) is characterized by limb malformations and urogenital defects. Mild bilateral shortening of the thumbs and great toes, caused primarily by shortening of the distal phalanx and/or the first metacarpal or metatarsal, is the most common limb malformation and results in impaired dexterity or apposition of the thumbs. Urogenital abnormalities include abnormalities of the ureters and urethra and various degrees of incomplete Müllerian fusion in females and hypospadias of variable severity with or without chordee in males. Vesicoureteral reflux, recurrent urinary tract infections, and chronic pyelonephritis are common; fertility is normal.
Nasodigitoacoustic syndrome, also called Keipert syndrome, is a rare congenital syndrome first described by J.A. Keipert and colleagues in 1973. The syndrome is characterized by a misshaped nose, broad thumbs and halluces, brachydactyly, sensorineural hearing loss, facial features such as hypertelorism, and developmental delay.
Ectrodactyly, split hand, or cleft hand involves the deficiency or absence of one or more central digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly (ectrodactyls) are often described as "claw-like" and may include only the thumb and one finger with similar abnormalities of the feet.
Heart-hand syndromes are a group of rare diseases that manifest with both heart and limb deformities.
Brachydactyly type D, also known as short thumbstub thumb, or clubbed thumb, is a disease clinically recognised by a thumb being relatively short and round with an accompanying wider nail bed. The distal phalanx of affected thumbs is approximately two-thirds the length of full-length thumbs. It is the most common type of brachydactyly, or shortness of digits, affecting approximately 2–3% of the population, and is associated with the HOXD13 gene, located on chromosome 2q31.1.
Hirschsprung's disease-type D brachydactyly syndrome is a very rare genetic disorder which is characterized by the partial absence of nerves in the intestines and hypoplasia of the thumb's distal phalange. It has been described in 4 males from a 2-generation American family. The inheritance pattern was hypothesized to be either X-linked recessive or autosomal dominant with reduced penetrance.
Angel-shaped phalango-epiphyseal dysplasia, also known as peripheral dysostosis, is a rare type of osteochondrodysplasia which is characterized by angel-shaped middle phalanges of the fingers and generalized metaphyseal dysplasia/delayed osseous age. Additional findings include joint hypermobility, hypodontia, and hip osteoarthritis. According to OMIM, 10 cases from multiple families have been described in medical literature. It is thought to be inherited in an autosomal dominant manner. According to ORPHA, 20 cases have been reported.
Anonychia-onychodystrophy with brachydactyly type B and ectrodactyly is a very rare autosomal dominant disorder which is characterized by onychodystrophy, anonychia, fifth finger brachydactyly, thumb digitalization, and missing to underdeveloped distal phalanges of the fingers. It has been described in multiple members of a 5-generation English family.
Heart-hand syndrome, Slovenian type is a rare autosomal dominant genetic disorder belonging to the heart-hand syndromes.
