A microduplication of the long range SHH limb regulator (ZRS) is associated with triphalangeal thumb-polysyndactyly syndrome.

BACKGROUND: Sonic hedgehog (SHH) plays an important role in defining the anterior-posterior axis in the developing limbs. A highly conserved non-coding sequence about approximately 1 Mb upstream from the sonic hedgehog gene (SHH) was shown to be a long range regulator for SHH expression in the limb bud. Point mutations within this non-coding regulatory region designated ZRS lead to ectopic expression of Shh in the anterior margin of the limb bud, as shown in mice, and cause the human triphalangeal thumb and polysyndactyly (TPT-PS) phenotype. Even though this association is well established, its molecular mechanism remains unclear. METHODS AND RESULTS: We investigated a large pedigree with variable TPT-PS. A single nucleotide exchange within the SHH limb regulator sequence was excluded, but locus specific microsatellite marker analyses confirmed a linkage to this region. Subsequently, array comparative genomic hybridisation (array CGH) was carried out using a submegabase whole human genome tiling path bacterial artificial chromosome (BAC) array revealing a microduplication in 7q36.3 in affected individuals. A duplicated region of 588,819 bp comprising the ZRS was identified by quantitative real-time polymerase chain reaction (qPCR) and direct sequencing. CONCLUSION: A novel microduplication in 7q36.3 results in a similar TPT-PS phenotype as caused by single nucleotide alterations in the ZRS, the limb specific SHH regulatory element. Duplications can be added to the growing list of mechanisms that cause abnormalities of long range transcriptional control.

Thumb duplication - simple surgery for a common problem?

Polydactyly is one of the most common congenital anomalies of the hand, and thumb duplication the most common manifestation of polydactyly. Despite this, the results of surgical treatment for thumb duplication are frequently disappointing, and deformities secondary to improperly executed reduction procedures often make further corrective surgery necessary. Examples of thumb duplication, their characteristic abnormal anatomy, and the complexity of surgical reduction procedures are illustrated.

Kirner's deformity treated by distal detachment of the flexor digitorum profundus tendon.

Kirner's deformity may be due to a very distal insertion of the flexor digitorum profundus tendon along the palmar surface of the distal phalanx of the small finger. Distal detachment of the flexor digitorum profundus tendon has already led to encouraging results. Intraoperative findings, surgical technique and results are shown.

Full-thickness skin grafts from the cubital fossa for syndactyly-release.

In syndactyly-release, skin defects along the sides of the fingers are usually covered with full-thickness skin grafts harvested from the groin. Since January 1997, we have been routinely harvesting full-thickness skin grafts from the cubital fossa instead. Skin grafts from the cubital fossa are softer and more pliable than those from the groin. Furthermore, they give a superior color match and cannot give rise to the growth of unsightly and embarrassing pubic hair in the hand. Donor-site morbidity seems to be nearly negligible, particularly if the donor site scar line is situated along one of the transverse skin creases of the cubital fossa. In cases of multiple syndactylies in a single hand, full-thickness skin grafts can be repeatedly harvested from the cubital fossa.

[The evolution of hand surgery in America]. / Wie in Amerika die Handchirurgie entstand1.

The beginnings of modern hand surgery strongly reflect those advances made in the United States during the early decades of the last century particularly concerning the treatment of infections of the hand and tendon injuries in the upper extremity. Although Sterling Bunnell fully deserves to be called the father of hand surgery and his monumental book, "Surgery of the Hand", published in 1944 equally deserves to be considered the Bible of hand surgery, we should and must remember other American pioneers of hand surgery, who, from 1900 to 1950 laid the foundation for our specialty.

Radiation dose rates from patients undergoing PET: implications for technologists and waiting areas.

Increasingly hospitals are showing an interest in developing their imaging services to include positron emission tomography (PET). There is therefore a need to be aware of the radiation doses to critical groups. To assess the effective whole-body dose received by technologists within our dedicated PET centre, each staff member was issued with a dose rate meter, and was instructed to record the time spent in contact with any radioactive source, the dose received per working day and the daily injected activity. On average each technologist administered 831 MBq per day. The mean whole-body dose per MBq injected was 0.02 microSv/MBq(-1). The average time of close contact (<2.0 m) with a radioactive source per day was 32 min. The average effective dose per minute close contact was 0.5 microSv/min(-1), which resulted in a mean daily effective dose of 14.4 microSv. No technologist received greater than 60 microSv (the current UK limit for non-classified workers) in any one day, and in general doses received were less than 24 microSv, the daily dose corresponding to the proposed new annual limit for non-classified workers of 6.0 mSv per annum. However, we recognise that the layout of nuclear medicine departments will not mirror our own. We therefore measured the instantaneous dose rates at 0.1, 0.5, 1.0 and 2.0 m from the mid-thorax on 115 patients immediately after injection, to provide estimates of the likely effective doses that might be received by technologists operating dual-headed coincidence detection systems, and others coming into contact in the waiting room with patients who have been injected with fluorine-18 fluorodeoxyglucose. The mean (95th percentile) dose rates measured at the four aforementioned distances were 391.7 (549.5), 127.0 (199.8), 45.3 (70.0) and 17.1 (30.0) microSv/h(-1), respectively. A number of situations have been modelled showing that, with correct planning, FDG studies should not significantly increase the effective doses to technologists. However, one possible area of concern is that, depending on the number of patients in a waiting area at any one time, accompanying persons may approach the limits set by the new UK IRR 1999 regulations for members of the public.

Radial subluxation of the connexus intertendineus at the MP joint of the little finger in musicians treated by connexus intertendineus proximalization.

Snapping at the MP joint of the little finger can occur when the extended and ulnarly abducted MP joint is flexed. In musicians, this is characterized by an annoying loss of fluid motion, and discomfort. Clinical examination reveals radial subluxation of the connexus intertendineus across the head of the fifth metacarpal to be the underlying problem, and surgical exploration confirms this. Operative treatment for radial subluxation of the connexus intertendineus must preserve the delicate balance of the extensor assembly of the fingers, including the otherwise underestimated connexus intertendineus itself. A simple and effective surgical procedure is presented.