Trps1 transcription factor regulates mineralization of dental tissues and proliferation of tooth organ cells

Mutations of the TRPS1 gene cause trichorhinophalangeal syndrome (TRPS), a skeletal dysplasia with dental abnormalities. TRPS dental phenotypes suggest that TRPS1 regulates multiple aspects of odontogenesis, including the tooth number and size. Previous studies delineating Trps1 expression throughout embryonic tooth development in mice detected strong Trps1 expression in dental mesenchyme, preodontoblasts, and dental follicles, suggesting that TRPS dental phenotypes result from abnormalities in early developmental processes. In this study, Trps1^+/- and Trps1^-/- mice were analyzed to determine consequences of Trps1 deficiency on odontogenesis. We focused on the aspects of tooth formation that are disturbed in TRPS and on potential molecular abnormalities underlying TRPS dental phenotypes. Microcomputed tomography analyses of molars were used to determine tooth size, crown shape, and mineralization of dental tissues. These analyses uncovered that disruption of one Trps1 allele is sufficient to impair mineralization of dentin in both male and female mice. Enamel mineral density was decreased only in males, while mineralization of the root dental tissues was decreased only in females. In addition, significantly smaller teeth were detected in Trps1^+/- females. Histomorphometric analyses of tooth organs showed reduced anterior-posterior diameter in Trps1^-/- mice. BrdU-incorporation assay detected reduced proliferation of mesenchymal and epithelial cells in Trps1^-/- tooth organs. Immunohistochemistry for Runx2 and Osx osteogenic transcription factors revealed changes in their spatial distribution in Trps1^-/- tooth organs and uncovered cell-type specific requirements of Trps1 for Osx expression. In conclusion, this study has demonstrated that Trps1 is a positive regulator of cell proliferation in both dental mesenchyme and epithelium, suggesting that the microdontia in TRPS is likely due to decreased cell proliferation in developing tooth organs. Furthermore, the reduced mineralization observed in Trps1^+/- mice may provide some explanation for the extensive dental caries reported in TRPS patients.

Effect of growth hormone therapy on severe short stature and skeletal deformities in a patient with combined Turner syndrome and Langer mesomelic dysplasia

BACKGROUND

Homozygous mutation of the short stature homeobox-containing gene, SHOX, results in Langer mesomelic dysplasia (LMD). Our case presented with severe short stature and skeletal deformities with Turner syndrome (TS) and a SHOX gene abnormality due to a downstream allele deletion in her normal X chromosome. Medical literature review did not reveal similar cases that were treated with GH therapy.

METHOD

We present an 11-yr-old with combined TS and LMD with severe short stature and skeletal deformities. She was studied for the effect of GH therapy on stature and skeletal deformities. Karyotype testing showed 45,X/46,X,idic(X). Genetic analysis of SHOX gene testing did not detect any exonic mutations. Interestingly, both alleles of the flanking marker DXYS233, a marker downstream of the 3' end of SHOX coding sequence, were absent with resultant LMD. GH therapy in the mean dose of 0.321 mg/kg/wk was administered for 4 yr (0.287, 0.355, 0.317, and 0.327 mg/kg/week in the first, second, third, and fourth years, respectively). Clinical data were reviewed.

RESULT

The growth rates of 3.46, 3.87, 2.3, and 0.7 cm/yr were observed in the first, second, third, and fourth years of the GH therapy, respectively. There was no clinical deterioration of the skeletal deformities.

CONCLUSION

There was a failure to achieve growth improvements with GH therapy for 4 years, but there was no worsening of the skeletal deformities. We conclude that GH therapy may not be beneficial in severe short stature due to combined TS and LMD resulting from homozygous SHOX deficiency.

A Novel Model Surgery Technique for LeFort III Advancement

Current techniques for model surgery and occlusal splint fabrication lack the ability to mark, measure and plan the position of the orbital rim for LeFort III and Monobloc osteotomies. This report describes a model surgery technique for planning the three dimensional repositioning of the orbital rims. Dual orbital pointers were used to mark the infraorbital rim during the facebow transfer. These pointer positions were transferred onto the surgical models in order to follow splint-determined movements. Case reports are presented to illustrate how the model surgery technique was used to differentiate the repositioning of the orbital rim from the occlusal correction in single segment and combined LeFort III/LeFort I osteotomies.

Lower eyelid entropion in Langer-Giedion syndrome

Langer-Giedion syndrome results from a genetic deletion on chromosome 8. Although redundant skin is part of Langer-Giedion syndrome, lower eyelid entropion and eyelid laxity have not been previously reported in the medical literature. We report a case of bilateral lower eyelid entropion in a patient with Langer-Giedion syndrome who successfully underwent entropion repair with anterior lamellar resection, lower eyelid retractor advancement, and lateral canthopexy. Although she has done well 6 months after surgery, we anticipate that laxity and eyelid instability will continue to develop with age, and additional reconstructive surgery may be required.

Langer-giedion syndrome with renal cyst

Here it is reported a 4-year-old boy with Langer-Giedion syndrome (Trichorhino phalangeal syndrome-II), who had characteristic features of TRP II, associated with multiple renal cysts hitherto unreported. This could be a new association in this syndrome that may serve to support the concept of contiguous gene syndrome in patients with TRP II.

Tibial hemimelia in Langer-Giedion syndrome-possible gene location for tibial hemimelia at 8q

We report on a girl with Langer-Giedion syndrome or tricho-rhino-phalangeal syndrome, type II (TRPS II) with deletion on 8q, and the unusual findings of bilateral tibial hemimelia and unilateral absence of the ulna. An 8-year-old boy with TRPS II with bilateral tibial hemimelia was reported by Turleau et al. [1982: Hum. Genet. 62:183-187]. The critical region for TRPS II is 8q24.1. Although no genes involving limb development in the human have been identified in this region, two mouse syndromes are localized to the homologous chromosome region of 9A1-A4 which involve limb abnormalities. We propose that a gene involved in limb development is contiguous with the TRPS II gene which, when deleted, may cause tibial hemimelia.

Langer-Giedion syndrome associated with submucous cleft palate

We report a 4-year-old girl with characteristic features of the Langer-Giedion syndrome (trichorhinophalangeal syndrome type II) who also had submucous cleft palate. When she underwent a palatoplasty, a diagnosis of Langer-Giedion syndrome was made because of the characteristic facial features, multiple exostoses, and partial deletion of the long arm of chromosome 8. This is the first case of trichorhinophalangeal syndrome associated with cleft palate. We review the clinical alterations of trichorhinophalangeal syndromes and differential diagnosis of Langer-Giedion syndrome from trichorhinophalangeal syndrome type I and hereditary multiple exostoses. We also describe the importance of trichorhinophalangeal syndrome in plastic surgery.

Langer-Giedion syndrome associated with scimitar syndrome

We describe an infant with Langer-Giedion syndrome combined with scimitar syndrome.

Tricho-rhino-phalangeal syndrome type II associated with epiglottic aplasia and congenital nephrotic syndrome

A male neonate with tricho-rhino-phalangeal syndrome type II (Langer-Giedion syndrome) and interstitial deletion of chromosome 8 with karyotype 46, XY, del (8) (q24.11-->q24.13) is reported. In addition to hypotrichosis of the scalp hair, abnormally bulbous nose and redundant skin, which are usually found in this syndrome, aplasia of the epiglottis and non-Finnish type congenital nephrotic syndrome were also present. He died of renal failure and respiratory failure at 11 days of age. Electron microscopy of renal necropsy showed foot process loss, focal thickening and splitting of the glomerular basement membrane and mesangial expansion. These have never been reported and could be new associations in this disease that may serve to support the concept of contiguous gene syndrome in patients with tricho-rhino-phalangeal syndrome.

[A case of Langer-Giedion syndrome (tricho-rhino-phalangeal syndrome type II) associated with epilepsy]

We reported here a case of Langer-Giedion syndrome (tricho-rhino-phalangeal syndrome (TRPS) type II) associated with epilepsy. TRPS type II is an uncommon genetic disease characterized by sparse, slowly growing scalp hair, pear-shaped nose, multiple cartilagenous exostosis and mental retardation associated with delayed speech development. This patient displayed typical features of this syndrome. He also showed arachnoid cyst in the frontal area on computer tomography of the brain, and paroximal activities on EEG. Chromosomal analysis revealed a partial deletion of the long arm of chromosome 8. He had afebrile convulsion which is a rare complication of this syndrome.

Trichorhinophalangeal syndrome, type I, with avascular necrosis of the femoral head

We report the case of a seven-year-old girl with peculiar facial traits who presented for right coxalgia of six weeks' duration. The phenotypic findings corresponded to a trichorhinophalangeal syndrome, type I, and the clinical, radiological and gammagraphic characteristics were indicative of avascular necrosis of the right femoral head, Legg-Perthes-Calvé disease.

Perthes-like disease and the tricho-rhino-phalangeal syndromes: the first black patient

The TRPS I has been reported in European, Asian, Australian, and North American populations. To the best of our knowledge, this is the first case reported in the black population. Like many patients with this syndrome, it was the presence of "Perthes-like" disease that eventually lead to the diagnosis. This hip complication is very common, and often bilateral. A review of the literature stresses the importance of early diagnosis in that many patients are presenting late with severe degenerative arthritis. When present, "Perthes-like" changes should direct the observer to look for the abnormal hair and facies that are typical of these syndromes. Radiographs of the hands should also be obtained which will usually reveal the characteristic cone-shaped epiphyses. Clinical or radiographic evidence of multiple cartilaginous exostoses is diagnostic of TRPS II in the presence of other stigmata of the tricho-rhino-phalangeal syndrome (TRPS I).