Brachydactyly type D | |
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Other names | Clubbed thumb, [1] thumb head, [2] short thumb, [3] [1] potter's thumb, [1] royal thumb, murderer's thumb, [1] hammer thumb, toe thumb, stubbed thumb, [4] stub thumb [5] [6] |
Unilateral brachydactyly type D in a 15-year-old female | |
X-ray of a normal thumb (left) and a thumb with brachydactyly type D (right) showing distal phalange brachyphalangy of said thumb. | |
Specialty | Medical genetics |
Brachydactyly type D, also known as short thumb, [3] [1] stub thumb, [5] [6] or clubbed thumb, [5] [6] is a genetic trait 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. [7]
Brachydactyly type D is a skeletal condition which exhibits a 'partial fusion or premature closing of the epiphysis with the distal phalanx of the thumb', according to Goodman et alia (1965). [6] J.K. Breithenbecher (1923) found that distal phalanges of short thumbs were one-half the length of full-length thumbs, while R.M. Stecher (1957) claimed that it is approximately two-thirds. The condition may either be unilateral (affecting one thumb) or bilateral (affecting both). [6]
A genetic trait, brachydactyly type D exhibits autosomal dominance and is commonly developed or inherited independently of other hereditary traits. The condition is associated with the HOXD13 gene, which is central in digital formation and growth. [5]
Various other studies supported an autosomal dominant pattern with reduced penetrance. [8]
A 1965 scientific study in Israel found that 3.05% of Israeli Arabs had one or two short thumbs, compared with 1.57% among Ashkenazi as well as non-Ashkenazi Jews. [6] However, as the survey's Arab test persons were mainly recruited from a handful of large and closely related clans living in a particular village, said percentage should be "considered with some reservation," according to Goodman et al. (1965).
Cases of short thumbs have also been found in Eastern Nepal for Jirel ethnic individuals from their participation in various epidemiologic studies. Some studies included taking radiographs of hands and wrists to examine their skeletal structure. Of the studied sample (which included 2,130 participants; 1,161 female and 969 male), 3.55% were found to have brachydactyly type D. [9]
The condition is known under numerous names. The most commonly used name is clubbed thumb, or club thumb. [10] [11] American researcher R.A. Hefner used the terms "short thumb" and "brachymegalodactylism" in 1924, [3] and "short thumb" has continued to be used in a few other studies since then, including the study that defined Rubinstein–Taybi syndrome in 1963. [1] "Stub thumb" is the common term preferred by the online database Online Mendelian Inheritance in Man [5] and was first used in a 1965 study. [6] Stub thumbs have also been called murderer's thumb (allegedly among fortune tellers), [6] wookie thumb, hammer thumb, bohemian thumb, and potter's thumb. [5]
The term "clubbed thumb" should not be confused with nail clubbing, which is a clinical sign associated with a number of diseases.[ citation needed ]
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 syndrome and the link between Carpenter syndrome and brachydactyly.
Cri du chat syndrome is a rare genetic disorder due to a partial chromosome deletion on chromosome 5. Its name is a French term referring to the characteristic cat-like cry of affected children. It was first described by Jérôme Lejeune in 1963. The condition affects an estimated 1 in 50,000 live births across all ethnicities and is more common in females by a 4:3 ratio.
Julia Bell MA Dubl (1901) MRCS LRCP (1920) MRCP (1926) FRCP (1938) was one of the pioneers of eugenics and human genetics. Her early career as a statistical assistant to Karl Pearson (1857–1936) marked the beginning of a lifelong professional association with the Galton Laboratory for National Eugenics at University College London. Bell's work as a human geneticist was based on her statistical investigations into the inheritance of anomalies and diseases of the eye, nervous diseases, muscular dystrophies, and digital anomalies.
Greig cephalopolysyndactyly syndrome is a disorder that affects development of the limbs, head, and face. The features of this syndrome are highly variable, ranging from very mild to severe. People with this condition typically have one or more extra fingers or toes (polydactyly) or an abnormally wide thumb or big toe (hallux).
Homeobox protein Hox-D13 is a protein that in humans is encoded by the HOXD13 gene. This gene belongs to the homeobox family of genes. The homeobox genes encode a highly conserved family of transcription factors that play an important role in morphogenesis in all multicellular organisms.
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.
Hereditary neuropathy with liability to pressure palsy (HNPP) is a peripheral neuropathy, a condition that affects the nerves. Pressure on the nerves can cause tingling sensations, numbness, pain, weakness, muscle atrophy and even paralysis of the affected area. In normal individuals, these symptoms disappear quickly, but in sufferers of HNPP even a short period of pressure can cause the symptoms to occur. Palsies can last from minutes or days to weeks or even months.
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.
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.
MURCS association is a very rare developmental disorder that primarily affects the reproductive and urinary systems involving MUllerian agenesis, Renal agenesis, Cervicothoracic Somite abnormalities. It affects only females.
Polysyndactyly is a congenital anomaly, combining polydactyly and syndactyly, in which affected individuals have an extra finger or toe that is connected, via fusing or webbing, to an adjacent digit.
Jordans' anomaly is a familial abnormality of white blood cell morphology. Individuals with this condition exhibit persistent vacuolation of granulocytes and monocytes in the peripheral blood and bone marrow. Jordans' anomaly is associated with neutral lipid storage diseases.
Familial opposable triphalangeal thumb duplication is a limb malformation syndrome and a type of pre-axial polydactyly, characterized by having duplicated opposable triphalangeal thumbs. This condition can be a symptom of other genetic disorders, such as Holt–Oram syndrome and Fanconi anemia. This trait is autosomal dominant and often runs in families. Sometimes big toe duplication, post-axial polydactyly, and syndactyly of the hand and feet can occur alongside this malformation Approximately 20 families with the condition have been described in medical literature.
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Brachydactyly-long thumb syndrome is a very rare genetic disorder which is characterized by symmetric brachydactyly of the fingers accompanied by an abnormally long thumb, hypomobility of the shoulder and metacarpo-phalangeal joints, and heart conduction defects. Small feet and hands, small shoulders accompanied with short clavicles, clinodactyly, pectus excavatum, mild limb shortening, cardiomegaly, and pulmonic stenosis murmur have also been reported. It was first discovered when D W Hollister et al. described 4 affected members belonging to a 3-generation family. No new cases have been reported since 1981. This disorder is inherited in an autosomal dominant manner.
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