A case of Aicardi syndrome associated with duplication event of Xp22 including SHOX

BACKGROUND

Aicardi syndrome is a neurodevelopmental disorder characterized by a triad of partial or complete agenesis of the corpus callosum, infantile spasms, and pathognomonic chorioretinal lacunae.

METHODS

Examination, multimodal imaging, and genetic testing were used to guide diagnosis.

RESULTS

We report a case of a pediatric patient who was initially diagnosed with refractory infantile spasms. The patient was unresponsive to conventional antiepileptic therapy, and genetic testing with whole exome and mitochondrial genome sequencing could not identify the underlying cause, so vigabatrin was initiated. The ophthalmic examination under anesthesia for vigabatrin toxicity screening revealed chorioretinal atrophy in the retinal periphery of both eyes, with two 3-disc diameter chorioretinal lacunae superotemporal and inferonasal to the optic nerve in the left eye. Given the neuroimaging findings of corpus callosum hypoplasia with polymicrogyria and ocular findings, the patient was diagnosed with Aicardi syndrome. Genetic testing revealed a novel duplication event at the Xp22 locus.

CONCLUSIONS

Aicardi syndrome, albeit a rare condition, should always be considered in the differential diagnosis when investigating a female child with refractory seizures in early childhood. Genetic testing may help further our understanding of AIS and the search for a genetic etiology.

Longitudinal assessment of bone health index as a measure of bone health in short-statured children before and during treatment with recombinant growth hormone

OBJECTIVES

The aim of our study was the longitudinal assessment of bone health index (BHI) in short-statured children during growth hormone (GH) treatment to estimate changes in their bone health.

METHODS

256 short-statured children (isolated GH deficiency (IGHD) n=121, multiple pituitary hormone deficiency (MPHD) n=49, intrauterine growth retardation (small for gestational age (SGA)) n=52, SHOX (short stature homeobox gene) deficiency n=9, Ullrich Turner syndrome (UTS) n=25) who started with GH between 2010 and 2018 were included. Annual bone ages (Greulich and Pyle, GP) and BHI were, retrospectively, analysed in consecutive radiographs of the left hand (BoneXpert software) from GH therapy start (T0) up to 10 years (T10) thereafter, with T max indicating the individual time point of the last available radiograph. The results are presented as the median (25 %/75 % interquartile ranges, IQR) and statistical analyses were performed using non-parametric tests as appropriate.

RESULTS

The BHI standard deviation scores (SDS) were reduced (-0.97, -1.8/-0.3) as bone ages were retarded (-1.6 years, -2.31/-0.97) in all patients before start of GH and were significantly lower in patients with growth hormone deficiency (GHD) (-1.04, -1.85/-0.56; n=170) compared to non-GHD patients (-0.79, -1.56/-0.01; n=86; p=0.022). BHI SDS increased to -0.17 (-1/0.58) after 1 year of GH (T1, 0.5-1.49, p<0.001) and to -0.20 (-1/-0.50, p<0.001) after 5.3 years (T max, 3.45/7.25).

CONCLUSIONS

BHI SDS are reduced in treatment-naive short-statured children regardless of their GH status, increase initially with GH treatment while plateauing thereafter, suggesting sustained improved bone health.

Diagnostic value of exfoliated tumor cells combined with DNA methylation in bronchoalveolar lavage fluid for lung cancer

BACKGROUND

To evaluate the diagnostic value of exfoliated tumor cells (ETCs) numbers combined with DNA methylation levels in bronchoalveolar lavage fluid (BALF) in lung cancer.

METHODS

BALF samples were collected from 43 patients with lung cancer and 23 with benign lung disease. ETCs were detected by the nano-enrichment method, and the methylation status of the short stature homeobox gene 2 (SHOX2) and the RAS association domain family 1, isoform A (RASSF1A) gene were detected by RT-PCR. The diagnostic value of each metric was evaluated by receiver operating characteristic curve analysis, specificity and sensitivity.

RESULTS

The sensitivity/specificity of RASSF1A and SHOX2 methylation detection were 44.12%/76.47% and 93.75%/87.50%, respectively. When "RASSF1A/SHOX2 methylation" was used as a positive result, the sensitivity increased to 88.24%, and the specificity decreased to 81.25%. When "RASSF1A + SHOX methylation" was used as positive, the sensitivity was reduced to 32.35%, but the specificity was increased to 100.00%. The sensitivity and specificity of ETCs detection in BALF were 89.47% and 16.67%, respectively. When "SHOX2/RASSF1A methylation + ETCs was used as a positive result, the sensitivity and specificity of the detection were 79.31% and 81.82%, respectively. When "SHOX2 + RASSF1A + ETCs" was used as positive, the sensitivity was 34.48% and the specificity was 90.91%. Receiver operating characteristic curve analysis showed that when SHOX2, RASSF1A methylation and ETCs were combined, the diagnostic sensitivity increased to 0.778.

CONCLUSION

ETCs counting in combination with SHOX2 and RASSF1A methylation assays in BALF samples has demonstrated excellent sensitivity for lung cancer diagnosis and is an effective complementary tool for clinical diagnosis of lung cancer.

The Genetic Landscape of Children Born Small for Gestational Age with Persistent Short Stature

INTRODUCTION

Among children born small for gestational age, 10-15% fail to catch up and remain short (SGA-SS). The underlying mechanisms are mostly unknown. We aimed to decipher genetic aetiologies of SGA-SS within a large single-centre cohort.

METHODS

Out of 820 patients treated with growth hormone (GH), 256 were classified as SGA-SS (birth length and/or birth weight <-2 SD for gestational age and life-minimum height <-2.5 SD). Those with the DNA triplet available (child and both parents) were included in the study (176/256). Targeted testing (karyotype/FISH/MLPA/specific Sanger sequencing) was performed if a specific genetic disorder was clinically suggestive. All remaining patients underwent MS-MLPA to identify Silver-Russell syndrome, and those with unknown genetic aetiology were subsequently examined using whole-exome sequencing or targeted panel of 398 growth-related genes. Genetic variants were classified using ACMG guidelines.

RESULTS

The genetic aetiology was elucidated in 74/176 (42%) children. Of these, 12/74 (16%) had pathogenic or likely pathogenic (P/LP) gene variants affecting pituitary development (LHX4, OTX2, PROKR2, PTCH1, POU1F1), the GH-IGF-1 or IGF-2 axis (GHSR, IGFALS, IGF1R, STAT3, HMGA2), 2/74 (3%) the thyroid axis (TRHR, THRA), 17/74 (23%) the cartilaginous matrix (ACAN, various collagens, FLNB, MATN3), and 7/74 (9%) the paracrine chondrocyte regulation (FGFR3, FGFR2, NPR2). In 12/74 (16%), we revealed P/LP affecting fundamental intracellular/intranuclear processes (CDC42, KMT2D, LMNA, NSD1, PTPN11, SRCAP, SON, SOS1, SOX9, TLK2). SHOX deficiency was found in 7/74 (9%), Silver-Russell syndrome in 12/74 (16%) (11p15, UPD7), and miscellaneous chromosomal aberrations in 5/74 (7%) children.

CONCLUSIONS

The high diagnostic yield sheds a new light on the genetic landscape of SGA-SS, with a central role for the growth plate with substantial contributions from the GH-IGF-1 and thyroid axes and intracellular regulation and signalling.

Pubertal boy presenting with mild disproportionate short stature

A boy aged 12 years was referred with short stature. He was born at term, of adequate weight (10-25th centile) and length (10-25th centile), which settled to just below the third centile from 18 months of age, with a growth deceleration in the last 6 months (growth velocity -2.1 standard deviation score, according to Tanner charts). He was otherwise asymptomatic. His mother's height was 155 cm, and father's height 158 cm, and he was growing near his target height centile (-2.26 SDS, <3rd centile).On examination, his height was -2.22 SDS, with normal weight and body mass index (BMI). Pubertal stage corresponded to Tanner 2, with a testicular volume of 4 mL. His legs and forearms appeared shorter, with arm span/height ratio 0.93 (normal value >0.965) and sitting height/height ratio 0.56 (slightly above the normal upper value of 0.55). He resembled his father, whose wrists were abnormally curved (figure 1). The patient's hand X-ray showed that bone age was similar to chronological age.

[Insufficient knowledge of the relationship between sex chromosome abnormalities and psychiatric diagnoses]

Sex chromosome abnormalities are among the most common genetic changes. The manifestations vary and may include growth abnormalities, specific appearance features, and other endocrinological and physical disorders, but also delayed psychomotor development, learning disabilities, and psychiatric conditions including ADHD and autism spectrum disorders. Increased knowledge about the relationship between sex chromosome abnormalities, development and psychiatric conditions would enable improved care of these patients.

Identification of a novel 15.5 kb SHOX deletion associated with marked intrafamilial phenotypic variability and analysis of its molecular origin

Haploinsufficiency of the short stature homeobox contaning SHOX gene has been shown to result in a spectrum of phenotypes ranging from Leri-Weill dyschondrosteosis (LWD) at the more severe end to SHOX-related short stature at the milder end of the spectrum. Most alterations are whole gene deletions, point mutations within the coding region, or microdeletions in its flanking sequences. Here, we present the clinical and molecular data as well as the potential molecular mechanism underlying a novel microdeletion, causing a variable SHOX-related haploinsufficiency disorder in a three-generation family. The phenotype resembles that of LWD in females, in males, however, the phenotypic expression is milder. The 15523-bp SHOX intragenic deletion, encompassing exons 3-6, was initially detected by array-CGH, followed by MLPA analysis. Sequencing of the breakpoints indicated an Alu recombination-mediated deletion (ARMD) as the potential causative mechanism.

Retinoic acid catabolizing enzyme CYP26C1 is a genetic modifier in SHOX deficiency

Mutations in the homeobox gene SHOX cause SHOX deficiency, a condition with clinical manifestations ranging from short stature without dysmorphic signs to severe mesomelic skeletal dysplasia. In rare cases, individuals with SHOX deficiency are asymptomatic. To elucidate the factors that modify disease severity/penetrance, we studied a three-generation family with SHOX deficiency. The variant p.Phe508Cys of the retinoic acid catabolizing enzyme CYP26C1 co-segregated with the SHOX variant p.Val161Ala in the affected individuals, while the SHOX mutant alone was present in asymptomatic individuals. Two further cases with SHOX deficiency and damaging CYP26C1 variants were identified in a cohort of 68 individuals with LWD The identified CYP26C1 variants affected its catabolic activity, leading to an increased level of retinoic acid. High levels of retinoic acid significantly decrease SHOX expression in human primary chondrocytes and zebrafish embryos. Individual morpholino knockdown of either gene shortens the pectoral fins, whereas depletion of both genes leads to a more severe phenotype. Together, our findings describe CYP26C1 as the first genetic modifier for SHOX deficiency.

The growth response to GH treatment is greater in patients with SHOX enhancer deletions compared to SHOX defects

OBJECTIVE

Short stature caused by point mutations or deletions of the short stature homeobox (SHOX) gene (SHOX haploinsufficiency (SHI)) is a registered indication for GH treatment. Patients with a SHOX enhancer deletion (SED) have a similar phenotype, but their response to GH is unknown. It is uncertain if duplications of SHOX or its enhancer (SDUP) cause short stature. This study aimed to describe the clinical characteristics and growth response to GH treatment in patients with aberrations of SHOX and its enhancers.

DESIGN

In this retrospective multi-center study (2002-March 2014) clinical information was available from 130 patients (72 SHI, 44 SED, and 14 SDUP) of whom 52 patients were treated with GH. We evaluated height, sitting height (SH), arm span, dysmorphic features and indicators of the growth response to GH (delta height SDS, height velocity, and index of responsiveness).

RESULTS

Patients with SEDs showed similar HtSDS to patients with SHI (-2.3 and -2.6, respectively, P=0.2), but they were less disproportionate (SH/height ratio SDS 2.0 vs 3.1 (P<0.01) and extremities/trunk ratio 2.57 vs 2.43 (P=0.03)). The 1st year growth response to GH treatment was significantly greater in prepubertal patients with SEDs than SHI. None of the patients with an SDUP was disproportionate and SDUP cosegregated poorly with short stature; their growth response to GH treatment (n=3) was similar to the other groups.

CONCLUSIONS

Patients with SEDs are equally short, but less disproportionate than patients with SHI, and show a greater response to GH.

Case report: long-term follow-up of a 45,X male with SHOX haploinsufficiency

The 45,X disorder of sexual differentiation (DSD) is a rare disorder. We report long-term follow-up of a 5-year-old African-American male whose evaluation for short stature revealed a karyotype of 45,X der(X)t(X;Y)(p22.3;p11.2)(SRY+). Presence of the SRY (sex-determining region Y) gene resulted in his male development. His chromosome abnormality also resulted in a deletion of the SHOX (short stature homeobox-containing) gene, which partly contributed to his short stature and skeletal features. He underwent normal spontaneous pubertal development, but his final height remained compromised due to advanced bone age, non-optimal response to recombinant human growth hormone (rhGH) treatment during the period of compliance and ultimately non-compliance with rhGH therapy. To our knowledge, this is the first case report describing long-term follow-up of a 45,X male DSD which highlights the similarities and differences from Turner syndrome females.

Increased cortical area and thickness in the distal radius in subjects with SHOX-gene mutation

INTRODUCTION

Short-stature homeobox (SHOX) gene haploinsufficiency may cause skeletal dysplasia including Léri-Weill Dyschondrosteosis (LWD), a clinical entity characterised by the triad of low height, mesomelic disproportion and Madelung's deformity of the wrist. Bone microarchitecture and estimated strength in adult SHOX mutation carriers have not been examined.

METHODS

Twenty-two subjects with a SHOX mutation including 7 males and 15 females with a median age of 38.8 [21.1-52.2] years were recruited from five unrelated families. The control group consisted of 22 healthy subjects matched on age and sex. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. Bone geometry, volumetric density, microarchitecture and finite element estimated (FEA) bone strength were measured using high-resolution peripheral quantitative computed tomography (HR-pQCT). A full region of interest (ROI) image analysis and height-matched ROI analyses adjusting for differences in body height between the two groups were performed.

RESULTS

Areal BMD and T-scores showed no significant differences between cases and controls. Total radius area was smaller in cases than controls (207 [176-263] vs. 273 [226-298] mm, p<0.01). Radius cortical bone area (74 ± 20 vs. 58 ± 17 mm(2), p=0.01) and thickness (1.16 ± 0.30 vs. 0.84 ± 0.26 mm, p<0.01) as well as total density (428 ± 99 vs. 328 ± 72 mg/cm(3), p<0.01) were higher in SHOX mutation carriers compared to controls. Radius trabecular bone area (119 [103-192] vs. 202 [168-247] mm(2), p<0.01) and trabecular number (1.61 [1.46-2.07] vs. 1.89 [1.73-2.08] mm(-1), p=0.01) were smaller in SHOX mutation carriers. Tibia trabecular thickness was lower in cases (0.067 ± 0.012 vs. 0.076 ± 0.012 mm, p=0.01). These results remained significant after adjustment for differences in body height and when restricting analyses to females. There were no differences in BMD, radius and tibia cortical porosity or FEA failure load between groups. A segment of cortical bone defect was identified in the distal radius adjacent to ulna in five unrelated SHOX mutation carriers.

CONCLUSION

Subjects with a SHOX mutation presented with a different bone geometry in radius and tibia while there were no differences in BMD or failure load compared to controls, suggesting that mutations in SHOX gene may have an impact on bone microarchitecture albeit not bone strength.

Radiological and clinical analysis of Madelung's deformity in children

INTRODUCTION

Madelung's deformity is a bone dysplasia that occurs predominantly in adolescent females, characterized by early epiphyseal growth arrest in the medial part of the distal radius. This leads to an upward and medial displacement of the radial joint surface, restricting range of motion.

OBJECTIVES

The objective of this study was to determine whether there was a link between clinical and radiological data in children with Madelung's deformity and to test the hypothesis of a relation between the deformity and a genetic mutation.

METHODS

A retrospective study recruited 13 patients with Madelung's deformity, with a mean age of 13.2 years (range, 8-18 years). Assessment comprised level of pain, range of motion and grip force, with standard AP and lateral wrist X-rays. Every patient except one underwent molecular genetic screening, adhering to current recommendations.

RESULTS

Pronation-supination, radial inclination and grip force were significantly impaired compared to normal results. All X-ray measurements were significantly abnormal, except for the lunate-covering ratio. Genetic mutation (SHOX) was systematic in the 12 patients screened.

DISCUSSION

Radiological deformity did not correlate with functional disturbance or pain. Non-acquired Madelung's deformity requires molecular screening for SHOX or XO mutation, which definitively diagnoses Léri-Weill dyschondrosteosis or Turner syndrome.

CONCLUSION

A larger series is necessary to confirm these preliminary results, which nevertheless suggest that non-acquired Madelung's deformity is not isolated but syndromic. Early detection of Léri-Weill or Turner syndrome is essential, due to their therapeutic specificities. LEVEL: IV.

Replacing Shox2 with human SHOX leads to congenital disc degeneration of the temporomandibular joint in mice

The temporomandibular joint (TMJ) consists in the glenoid fossa arising from the otic capsule through intramembranous ossification, the fibrocartilaginous disc and the condyle, which is derived from the secondary cartilage by endochondral ossification. We have reported previously that cranial neural-crest-specific inactivation of the homeobox gene Shox2, which is expressed in the mesenchymal cells of the maxilla-mandibular junction and later in the progenitor cells and perichondrium of the developing chondyle, leads to dysplasia and ankylosis of the TMJ and that replacement of the mouse Shox2 with the human SHOX gene rescues the dysplastic and ankylosis phenotypes but results in a prematurely worn out articular disc. In this study, we investigate the molecular and cellular bases for the prematurely worn out articular disc in the TMJ of mice carrying the human SHOX replacement allele in the Shox2 locus (termed Shox2 (SHOX-KI/KI)). We find that the developmental process and expression of several key genes in the TMJ of Shox2 (SHOX-KI/KI) mice are similar to that of controls. However, the disc of the Shox2 (SHOX-KI/KI) TMJ exhibits a reduced level of Collagen I and Aggrecan, accompanied by increased activities of matrix metalloproteinases and a down-regulation of Ihh expression. Dramatically increased cell apoptosis in the disc was also observed. These combinatory cellular and molecular defects appear to contribute to the observed disc phenotype, suggesting that, although human SHOX can exert similar functions to mouse Shox2 in regulating early TMJ development, it apparently has a distinct function in the regulation of those molecules that are involved in tissue homeostasis.

GH treatment to final height produces similar height gains in patients with SHOX deficiency and Turner syndrome: results of a multicenter trial

CONTEXT

Growth impairment in short stature homeobox-containing gene (SHOX) deficiency and Turner syndrome share a similar etiology. Because of the established effect of GH treatment on height in patients with Turner syndrome, we hypothesized that GH therapy would also stimulate growth in patients with SHOX deficiency.

OBJECTIVE

Our objectives were to evaluate long-term efficacy of GH treatment in short patients with SHOX deficiency and to compare the effect on final (adult) height (FH) in patients with SHOX deficiency and Turner syndrome.

DESIGN AND SETTING

A prospective, multinational, open-label, randomized 3-arm study consisting of a 2-year control period and a subsequent extension period to FH. The treatment groups were 1) SHOX-D-C/GH (untreated during the control period, GH-treated during the extension), 2) SHOX-D-GH/GH, and 3) Turner-GH/GH (GH-treated during both study periods).

PATIENTS

Short-statured prepubertal patients with genetically confirmed SHOX deficiency (n = 49) or Turner syndrome (n = 24) who participated in the extension.

INTERVENTION

Depending on the study arm, patients received a daily sc injection of 0.05 mg/kg recombinant human GH from start of the study or start of the extension until attainment of FH or study closure.

RESULTS

Height SD score gain from start of GH treatment to FH was similar between the combined SHOX-deficient groups (n = 28, 1.34 ± 0.18 [least-squares mean ± SE]) and the Turner group (n = 19, 1.32 ± 0.22). In this FH population, 57% of the patients with SHOX deficiency and 32% of the patients with Turner syndrome achieved a FH greater than -2 SD score.

CONCLUSIONS

GH treatment in short children with SHOX deficiency showed similar long-term efficacy as seen in girls with Turner syndrome.

Prepubertal girls with Turner syndrome and children with isolated SHOX deficiency have similar bone geometry at the radius

CONTEXT

The low bone mineral density (BMD) and alterations in bone geometry observed in patients with Turner syndrome (TS) are likely caused by hypergonadotropic hypogonadism and/or by haploinsufficiency of the SHOX gene.

OBJECTIVE

Our objective was to compare BMD, bone geometry, and strength at the radius between prepubertal girls with TS and children with isolated SHOX deficiency (SHOX-D) to test the hypothesis that the TS radial bone phenotype may be caused by SHOX-D.

DESIGN AND SETTING

This comparative cross-sectional study was performed between March 2008 and May 2011 in 5 large centers for pediatric endocrinology.

PATIENTS

Twenty-two girls with TS (mean age 10.3 years) and 10 children with SHOX-D (mean age 10.3 years) were assessed using peripheral quantitative computed tomography of the forearm.

MAIN OUTCOMES

BMD, bone geometry, and strength at 4% and 65% sites of the radius were evaluated.

RESULTS

Trabecular BMD was normal in TS (mean Z-score = -0.2 ± 1.1, P = .5) as well as SHOX-D patients (mean Z-score = 0.5 ± 1.5, P = .3). At the proximal radius, we observed increased total bone area (Z-scores = 0.9 ± 1.5, P = .013, and 1.5 ± 1.4, P = .001, for TS and SHOX-D patients, respectively) and thin cortex (Z-scores = -0.7 ± 1.2, P = 0.013, and -2.0 ± 1.2, P < .001, respectively) in both groups. Bone strength index was normal in TS as well as SHOX-D patients (Z-scores = 0.3 ± 1.0, P = .2, and 0.1 ± 1.3, P = .8, respectively).

CONCLUSIONS

The similar bone geometry changes of the radius in TS and SHOX-D patients support the hypothesis that loss of 1 copy of SHOX is responsible for the radial bone phenotype associated with TS.

Height matters-from monogenic disorders to normal variation

Height is a classic polygenic quantitative trait with a high level of heritability. As it is a simple and stable parameter to measure, height is a model for both common, complex disorders and monogenic, Mendelian disease. In this Review, we examine height from the perspective of monogenic and complex genetics and discuss the lessons learned so far. We explore several examples of rare sequence variants with large effects on height and compare these variants to the common variants identified in genome-wide association studies that have small effects on height. We discuss how copy number changes or genetic interactions might contribute to the unidentified aspects of the heritability of height. We also ask whether information derived from genome-wide association studies on specific loci in the vicinity of genes can be used for further research in clinical paediatric endocrinology. Furthermore, we address key challenges that remain for gene discovery and for the transition of moving from genomic localization to mechanistic insights, with an emphasis on using next-generation sequencing to identify causative variants of people at the extremes of height distribution.

Clinical and molecular characterization of Chilean patients with Léri-Weill dyschondrosteosis

AIM

Léri-Weill dyschondrosteosis (LWD) is a mesomelic dysplasia with disproportionate short stature associated with short stature homeobox-containing gene (SHOX) haploinsufficiency. The objective of this study was to improve the diagnosis of patients with suspected LWD through molecular analysis.

METHODS

Twelve patients from 11 families with a clinical diagnosis of LWD were analyzed with multiplex ligation-dependent probe amplification to detect deletions and duplications of SHOX and its enhancer regions. High resolution melting and sequencing was employed to screen for mutations in SHOX coding exons.

RESULTS

The molecular-based screening strategy applied in these patients allowed detection of five SHOX deletions and two previously unreported SHOX missense mutations.

CONCLUSION

Molecular studies confirmed the clinical diagnosis of LWD in seven out of 12 patients, which provided support for therapeutic decisions and improved genetic counseling in their families.

The homeobox transcription factor HOXA9 is a regulator of SHOX in U2OS cells and chicken micromass cultures

The homeobox gene SHOX encodes for a transcription factor that plays an important role during limb development. Mutations or deletions of SHOX in humans cause short stature in Turner, Langer and Leri-Weill syndrome as well as idiopathic short stature. During embryonic development, SHOX is expressed in a complex spatio-temporal pattern that requires the presence of specific regulatory mechanisms. Up to now, it was known that SHOX is regulated by two upstream promoters and several enhancers on either side of the gene, but no regulators have been identified that can activate or repress the transcription of SHOX by binding to these regulatory elements. We have now identified the homeodomain protein HOXA9 as a positive regulator of SHOX expression in U2OS cells. Using luciferase assays, chromatin immunoprecipitation and electrophoretic mobility shift assays, we could narrow down the HOXA9 binding site to two AT-rich sequences of 31 bp within the SHOX promoter 2. Virus-induced Hoxa9 overexpression in a chicken micromass model validated the regulation of Shox by Hoxa9 (negative regulation). As Hoxa9 and Shox are both expressed in overlapping regions of the developing limb buds, a regulatory relationship of Hoxa9 and Shox during the process of limb development can be assumed.

The SHOX gene and the short stature. Roundtable on diagnosis and treatment of short stature due to SHOX haploinsufficiency: how genetics, radiology and anthropometry can help the pediatrician in the diagnostic process Padova (April 20th, 2011)

The growth of the human body depends from a complex interaction between nutritional, environmental and hormonal factors and by a large number of different genes. One of these genes, short stature homeobox (SHOX), is believed to play a major role in growth. SHOX haploinsufficiency is associated with a wide spectrum of conditions, all characterized growth failure such as Leri-Weill dyschondrosteosis, Turner syndrome, short stature with subtle auxological and radiological findings and the so called "idiopathic short stature" (short stature with no specific findings other than growth failure). The document was prepared by a multidisciplinary team (paediatric endocrinologists, paediatrician, radiologist, geneticist and epidemiologist) to focus on the investigation of children with suspected SHOX- deficiency (SHOX-D) for an early identification and a correct diagnostic work - up of this genetic disorder. On the basis of a number of screening studies, SHOX-D appears to be a relatively frequent cause of short stature. The following recommendations were suggested by our multidisciplinary team: (i) a careful family history, measurements of body proportions and detection of any dysmorphic features are important for the suspect of a genetic disorder ,(ii)the presence of any combination of the following physical findings, such as reduced arm span/height ratio, increased sitting height/height ratio, above average BMI, Madelung deformity, cubitus valgus, short or bowed forearm, dislocation of the ulna at the elbow, or the appearance of muscular hypertrophy, should prompt the clinician to obtain a molecular analysis of the SHOX region, (iii) it is of practical importance to recognise early or mild signs of Madelung deformity on hand and wrist radiographs, (iv) growth hormone ,after stimulation test, is usually normal. However, treatment with rhGH may improve final adult height; the efficacy of treatment is similar to that observed in those treated for Turner syndrome.

Genotypes and phenotypes of children with SHOX deficiency in France

CONTEXT

The prevalence of SHOX deficiency in children with short stature (SS) is variable in the literature and various genotypes have been identified.

OBJECTIVES

The aim of our study was to determine the frequency and distribution of SHOX genotypes in a large sample of children with SS in France.

DESIGN, SETTING, AND PATIENTS

Children were enrolled in 38 French pediatric endocrinology centers and were either diagnosed with Leri-Weill syndrome (LWS), idiopathic short stature (ISS), or disproportionate short stature (DSS).

INTERVENTION AND MAIN OUTCOME MEASURE

SHOX analysis was performed centrally as part of the Genetics and Neuroendocrinology of Short Stature International Study observational study. We compared patients with (SHOX-D) and without SHOX deficiency (non-SHOX-D).

RESULTS

Among the 537 patients tested [58.3% females, mean age 11.0 (4.2) yr], 27.7% had SHOX deficiency (LWS, 48.9%; ISS, 16.9%; DSS, 18.8%). Mean height [-2.3 (0.9) sd score] was similar in SHOX-D and non-SHOX-D patients. The majority of SHOX-D patients with LWS had either a deletion encompassing SHOX or a point mutation (69%), whereas 59% of those with ISS had a deletion downstream of SHOX in the enhancer region. The height of the parents carrying a deletion downstream of SHOX was higher than the height of the parents carrying the other gene anomalies.

CONCLUSIONS

SHOX deletions and point mutations as well as downstream SHOX enhancer deletions were identified in almost one third of the patients tested. An anomaly in this latter region seemed to be linked to a milder phenotype. Although further confirmation is needed, we suggest that the enhancer region should be systematically analyzed in patients suspected of SHOX deficiency.

New roles of SHOX as regulator of target genes

The homeobox gene SHOX encodes a transcription factor which is important for normal limb development. Approximately 5 to 10% of short patients exhibit a mutation or deletion in either the SHOX gene or its downstream enhancer regions. In humans, SHOX deficiency has been associated with various short stature syndromes as well as non-syndromic idiopathic short stature. A common feature of these syndromes is disproportionate short stature with a particular shortening of the forearms and lower legs. Madelung deformity, cubitus valgus, high-arched palate and muscular hypertrophy also differed markedly between patients with or without SHOX gene defects. A clinical trial in patients with SHOX deficiency and Turner syndrome demonstrated highly significant growth hormone-stimulated increases in height velocity and height SDS in both groups. Employing microarray analyses and cell culture experiments, a strong effect of SHOX on the expression of the natriuretic peptide BNP and the fibroblast growth factor receptor gene FGFR3 could be demonstrated. We found that BNP was positively regulated, while Fgfr3 was negatively regulated by SHOX. A regulation that occurs mainly in the mesomelic segments, a region where SHOX is known to be strongly expressed, offers a possible explanation for the phenotypes seen in patients with FGFR3 (e.g. achondroplasia) and SHOX defects (e.g. Léri-Weill dyschondrosteosis).

Aberrations in pseudoautosomal regions (PARs) found in infertile men with Y-chromosome microdeletions

CONTEXT

The pseudoautosomal regions (PARs) of the Y-chromosome undergo meiotic recombination with the X-chromosome. PAR mutations are associated with infertility and mental and stature disorders.

OBJECTIVE

The aim of the study was to determine whether men with Y-chromosome microdeletions have structural defects in PARs.

DESIGN AND PARTICIPANTS

Eighty-seven infertile men with Y-chromosome microdeletions and 35 controls were evaluated for chromosomal rearrangements using commercial or custom (X- and Y-chromosome) array comparative genomic hybridization or by quantitative PCR of selected PAR genes. Multisoftware-defined chromosomal gains or losses were validated by quantitative PCR and FISH.

RESULTS

Array comparative genomic hybridization confirmed the AZF deletions identified by multiplex PCR. All men with Y-chromosome microdeletions and an abnormal karyotype displayed PAR abnormalities, as did 10% of men with Y-chromosome microdeletions and a normal karyotype. None of the control subjects or infertile men without Y-chromosome microdeletions had PAR duplications or deletions. SHOX aberrations occurred in 14 men (nine gains and five losses); four were short in stature (<10th percentile), and one was tall (>95th percentile). In contrast, the height of 23 men with Y-chromosome microdeletions and normal PARs was average at 176.8 cm (50th percentile).

CONCLUSIONS

Y-chromosome microdeletions can include PAR defects causing genomic disorders such as SHOX, which may be transmitted to offspring. Previously unrecognized PAR gains and losses in men with Y-chromosome microdeletions may have consequences for offspring.

Update in growth hormone therapy of children

Although recombinant human GH (rhGH) has been available since 1985, there are several questions related to its use that remain unanswered. The Entrez-PubMed search engine was used to conduct a review of publications appearing since 2007 that address growth and GH treatment. Recent publications related to the diagnosis of GH deficiency, genetics of growth, the use of rhGH in different genetic conditions, in idiopathic short stature, and in puberty, and strategies to adjust rhGH dose were reviewed. New studies investigating the genetics of growth and the response to rhGH therapy in different groups are helping in the understanding of the physiology of normal growth. Although in most children treated with rhGH there is a short-term benefit, the clinical relevance of the benefits after long-term treatment in some conditions remains unclear. The challenges are to define milder forms of GH deficiency and to assess the relevance of the benefits, if any, caused by rhGH in different patient populations and the best therapeutic approach for these patients. Well-designed long-term studies using anthropometric, genetic, and laboratory data that will also assess long-term quality of life benefits are needed to help clinicians select patients to initiate treatment with rhGH and to adjust treatment to improve outcome.

Clinical and molecular evaluation of SHOX/PAR1 duplications in Leri-Weill dyschondrosteosis (LWD) and idiopathic short stature (ISS)

CONTEXT

Léri-Weill dyschondrosteosis (LWD) is a skeletal dysplasia characterized by disproportionate short stature and the Madelung deformity of the forearm. SHOX mutations and pseudoautosomal region 1 deletions encompassing SHOX or its enhancers have been identified in approximately 60% of LWD and approximately 15% of idiopathic short stature (ISS) individuals. Recently SHOX duplications have been described in LWD/ISS but also in individuals with other clinical manifestations, thus questioning their pathogenicity.

OBJECTIVE

The objective of the study was to investigate the pathogenicity of SHOX duplications in LWD and ISS.

DESIGN AND METHODS

Multiplex ligation-dependent probe amplification is routinely used in our unit to analyze for SHOX/pseudoautosomal region 1 copy number changes in LWD/ISS referrals. Quantitative PCR, microsatellite marker, and fluorescence in situ hybridization analysis were undertaken to confirm all identified duplications.

RESULTS

During the routine analysis of 122 LWD and 613 ISS referrals, a total of four complete and 10 partial SHOX duplications or multiple copy number (n > 3) as well as one duplication of the SHOX 5' flanking region were identified in nine LWD and six ISS cases. Partial SHOX duplications appeared to have a more deleterious effect on skeletal dysplasia and height gain than complete SHOX duplications. Importantly, no increase in SHOX copy number was identified in 340 individuals with normal stature or 104 overgrowth referrals.

CONCLUSION

MLPA analysis of SHOX/PAR1 led to the identification of partial and complete SHOX duplications or multiple copies associated with LWD or ISS, suggesting that they may represent an additional class of mutations implicated in the molecular etiology of these clinical entities.

The jumping SHOX gene--crossover in the pseudoautosomal region resulting in unusual inheritance of Leri-Weill dyschondrosteosis

CONTEXT

During meiosis I, the recombination frequency in the pseudoautosomal region on Xp and Yp (PAR1) in males is very high. As a result, mutated genes located within the PAR1 region can be transferred from the Y-chromosome to the X-chromosome and vice versa.

PATIENTS

Here we describe three families with SHOX abnormalities resulting in Leri-Weill dyschondrosteosis or Langer mesomelic dysplasia.

RESULTS

In about half of the segregations investigated, a transfer of the SHOX abnormality to the alternate sex chromosome was demonstrated.

CONCLUSIONS

Patients with an abnormality of the SHOX gene should receive genetic counseling as to the likelihood that they may transmit the mutation or deletion to a son as well as to a daughter.

Short stature caused by isolated SHOX gene haploinsufficiency: update on the diagnosis and treatment

Heterozygous SHOX defects are observed in about 50 to 90% of patients with Leri-Weill dyschondrosteosis (LWD), a common dominant inherited skeletal dysplasia; and in 2 to 15% of children with idiopathic short stature (ISS), indicating that SHOX defects are the most important monogenetic cause of short stature. In addition, children selected by disproportionate idiopathic short stature had a higher frequency of SHOX mutations (22%). A careful clinical evaluation of family members with short stature is recommended since it usually revealed LWD patients in families first classified as having ISS or familial short stature. SHOX-molecular analysis is indicated in families with LWD and ISS children with disproportionate short stature. Treatment with recombinant human growth hormone is considered an accepted approach to treat short stature associated with isolated SHOX defect. Here we review clinical, molecular and therapeutic aspects of SHOX haploinsufficiency.

Trisomy of the short stature homeobox-containing gene (SHOX) due to duplication/deletion of the X chomosome: clinical implications on the stature

BACKGROUND

The karyotypes of 2 patients with abnormal stature and different phenotypes revealed one similar structural abnormality in the X chromosome by conventional cytogenetic studies and fluorescence in situ hybridization analysis (FISH). FISH strongly suggested the presence of two copies of the SHOX gene in the der(X) chromosome.

PATIENTS AND RESULTS

Patient 1 is a teenager girl with tall stature, behavioral disturbances and normal pubertal development. The abnormal X chromosome was present in all cells studied. Parent's karyotypes were normal. Patient 2 is a girl with gonadal dysgenesis, mild Turner syndrome phenotype and short stature. The karyotype was a mosaic 45,X/46,X,r(X) and der(X) chromosome presented in most metaphases of the cell lines. Parent's karyotypes were normal. Nearly all duplication of Xp and partial deletion of the long arm (Xq) from Xq27 or Xq21 to Xqter, in cases 1 and 2, respectively, were observed. In both patients, duplication of Xp translocated to deleted Xq occurred leading to a triplication of the pseudoautosomal region 1 (PAR1) where the SHOX gene is located (Xp22.3).

CONCLUSIONS

We propose that in some cases of trisomy for the SHOX gene, the effect of overdosage per se may affect the stature, even in patients with preserved ovarian function (case 1), and that estrogen deprivation may not always be a contributor for tall stature (case 2).

Epidemiology of SHOX deficiency

Deletion of short stature homeobox-containing (SHOX) gene, in the pseudoautosomal region (PAR1) of X and Y chromosomes, is an important cause of short stature. Homozygous loss of SHOX results in the more severe Langer mesomelic dysplasia, while SHOX haploinsufficiency cause a wide spectrum of short stature phenotypes, including patients with Turner syndrome, Leri Weill dyschondrosteosis (LWD), and idiopathic short stature (ISS). In Turner syndrome, haploinsufficiency of SHOX gene, as well as short stature, are present in 100%; nevertheless, SHOX deficiency accounts for only two-thirds of Turner patients' short stature. In LWD the prevalence of SHOX gene anomalies varies from 56% to 100%. This wide range might be due to different factors such as selection criteria of patients, sample size, and method used for screening SHOX mutations. The real challenge is to establish the prevalence of SHOX deficiency in ISS children given that published studies have reported this association with a very broad frequency range varying from 1.5% to 15%. An important variable in these studies is represented by the method used for screening SHOX mutations and sometimes by differences in patient selection. Short stature is present by definition in 3 out of 100 subjects; if we consider a frequency of SHOX defects of 3% among ISS, we should expect a population prevalence of 1 in 1000. This prevalence would be higher than that of GH deficiency (1:3,500) and of Turner syndrome (1:2,500 females), suggesting that SHOX deficiency could be one of the most frequent monogenetic causes of short stature.

The SHOX region and its mutations

The short stature homeobox-containing (SHOX) gene lies in the pseudoautosomal region 1 (PAR1) that comprises 2.6 Mb of the short-arm tips of both the X and Y chromosomes. It is known that its heterozygous mutations cause Leri-Weill dyschondrosteosis (LWD) (OMIM #127300), while its homozygous mutations cause a severe form of dwarfism known as Langer mesomelic dysplasia (LMD) (OMIM #249700). The analysis of 238 LWD patients between 1998 and 2007 by multiple authors shows a prevalence of deletions (46.4%) compared to point mutations (21.2%). On the whole, deletions and point mutations account for about 67% of LWD patients. SHOX is located within a 1000 kb desert region without genes. The comparative genomic analysis of this region between genomes of different vertebrates has led to the identification of evolutionarily conserved non-coding DNA elements (CNE). Further functional studies have shown that one of these CNE downstream of the SHOX gene is necessary for the expression of SHOX; this is considered to be typical "enhancer" activity. Including the enhancer, the overall mutation of the SHOX region in LWD patients does not hold in 100% of cases. Various authors have demonstrated the existence of other CNE both downstream and upstream of SHOX regions. The resulting conclusion is that it is necessary to reanalyze all LWD/LMD patients without SHOX mutations for the presence of mutations in the 5'- and 3'-flanking SHOX regions.

Different approaches in the molecular analysis of the SHOX gene dysfunctions

Deficit of the short stature homeobox containing gene (SHOX) accounts for 2.15% of cases of idiopathic short stature (ISS) and 50-100% of cases of Leri-Weill dyschondrosteosis (LWD). It has been demonstrated that patients with SHOX deficit show a good response to treatment with GH. Thus, the early identification of SHOX alterations is a crucial point in order to choose the best treatment for ISS and LWD patients. In this study, we analyze the most commonly used molecular techniques for the detection of SHOX gene alterations. multiple ligation-dependent probe amplification analysis appears to represent the gold standard for the detection of deletion involving the SHOX gene or the enhancer region, being able to show both alterations in a single assay.

Auxological and anthropometric evaluation in skeletal dysplasias

Anthropometry is the technique of expressing body shape in quantitative terms. The measurements are compared with the standard growth curves for the general population and expressed as a SD score or percentiles. The comparison of the different parameters with normal standards requires: standardized landmarks on the body, standardized methods of taking measurements, and standard equipment. Skeletal dysplasias generally present with disproportionate short stature, that may be caused primarily by a short trunk or short limbs. If short limbs are observed, the reduction may affect the proximal (rhizomelic), the middle (mesomelic) or distal (acromelic) segments. Anthropometric measurements should include all the segments of the arms and the legs with a comparison with the normal standards for height age. Short stature homeobox- containing (SHOX) gene defects determine a highly variable phenotype, that includes an osteochondrodysplasia with mesomelic short stature and Madelung deformity, but also presentations without evident malformations. Anthropometric indicators of SHOX deficiency are: disproportionate short stature, reduction of lower limb, reduction of the ratio between arm span and forearm length with respect to height, increase in the sitting/ height stature ratio, increase in limb circumference (arm, forearm, thigh, and leg) with respect to height and increased body mass index. In some forms of skeletal dysplasias and in particular in SHOX gene anomalies that have many characteristics superimposable to idiopathic short stature, only an accurate auxo-anthropometric and dysmorphologic evaluation enable us to propose, fairly accurately, the subjects for the gene study.

Bone dysplasias: the A, B, C of radiographic interpretation

The skeletal dysplasias are a group of genetic disorders affecting skeletal development and maintenance, usually manifesting in childhood with disproportionate short stature. Although individually rare, they are not infrequent as a group. An accurate diagnosis is crucial for prevention and/or treatment of complications, estimate of child's growth, and proper genetic counseling. Radiology is the mainstay of diagnosis. Recognition of single radiographic signs or patterns of anomalies is required to reach the correct diagnosis. The radiographic features of Leri-Weill syndrome and Langer mesomelic dwarfism, two skeletal dysplasias caused by a defect in the short stature homeobox-containing gene, are briefly discussed.

The SHOX gene: a new indication for GH treatment

Short stature homeobox-containing (SHOX) gene mutations causing haploinsufficiency have been reported in idiopathic short stature, but the real prevalence of this defect in the population with growth failure is debated. Based on current data, the prevalence of SHOXdefect (SHOX-D) has been calculated to have occurred in at least 1 in 2,000 children. This occurrence rate is higher than that of classic GH deficiency or Turner syndrome. In all probability, the real prevalence of SHOX-D will increase in the future with the improvement of the genetic analysis with investigations for point mutations in the enhancer sequences or for deletions in other parts of this region. A selection criterion to individuate the most appropriate candidates eligible for the SHOX region analysis has been suggested based on the evaluation of a disproportional short stature. The efficacy of GH treatment in these patients has recently been demonstrated with results that are similar to those observed in Turner syndrome.

A short history of the initial discovery of the SHOX gene

Already in 1981 Davis had reported that small Yp terminal deletion resulted in short stature and, basing his findings on Davis's results, on the results of other publications, and on his own observations that Xp terminal deletions normally result in short stature regardless of the breakpoints, in 1993 Ogata suggested that a growth gene was located in the pseudoautosomal region (PAR) and that haploinsufficiency of the growth gene actually caused short stature as a dominant phenotype. Rao et al. in 1997 cloned a gene from the distal part of the PAR and gave it the name SHOX for "short stature homeobox-containing" gene. SHOX is expressed from an inactive X chromosome and an active X and a normal Y chromosome, indicating that SHOX produces the dosage effect in sex chromosome aberrations. In the same year, both Ellison and Rao demonstrated that SHOX is most clearly expressed in bone marrow fibroblasts, thus suggesting that SHOX has a particular importance in bone growth and maturation.

Growth hormone therapy in patients with short stature homeobox-gene (SHOX) deficiency

Short stature homeobox (SHOX) gene is located in the pseudoautosomal region 1 on the distal end of the X and Y chromosomes at Xp22.3 and Yp11.3. The haploinsufficiency of SHOX is correlated with short stature, Leri-Weill dyschondrosteosis, and Langer mesomelic dysplasia. Subjects with Turner syndrome (TS) present a SHOX haploinsufficiency that appears to be substantially responsible for their short stature. Several studies have shown a positive response to GH therapy in patients with TS. Short children with SHOX haploinsufficiency do not spontaneously catch up to attain a normal final height. Considering the positive effects obtained in patients with TS, GH therapy has been proposed for short stature due to isolated SHOX haploinsufficiency. The aim of this paper is to summarize the current data on GH administration in patients with SHOX haploinsufficiency. The conclusion is that GH therapy, at the same dosage used in patients with TS, induces a sustained catch-up growth and a height velocity and adult height gain in short patients with SHOX haploinsufficiency.

SHOX mutation as a rare disease: molecular diagnosis and growth hormone treatment supported by the Italian public health system

Short stature homeobox-containing (SHOX) gene deficiency is acknowledged under the term "dyschondrosteosis", which is included in the family of congenital osteodystrophies. Under current regulations, the cost of the genetic testing and treatment with GH in children with short stature, and SHOX gene deficiency may be reimbursed. Prescription of costs exemption is subject to the identification of the regional centers qualified to diagnose congenital osteodystrophies (RNG060). The centers qualified to diagnose and treat "dyschondrosteosis" have been identified in only a few regions, whereas in other regions centers for the diagnosis and treatment of congenital osteodystrophies have been identified, and in still others, no specific centers have been identified yet. Treatment with GH as indicated by European Medicines Agency (EMEA) for people with short stature and evidence of SHOX gene deficiency is governed by Agenzia Italiana del Farmaco (AIFA) note number 39. The latest version does not provide for the medication to be directly reimbursed by the National Health Service, although it may be prescribed for patients with well-defined auxological characteristics, subject to the prior authorization of the regional commission qualified to monitor the use of the GH. Therefore, a diagnostic/ therapeutic course for patients with short stature with SHOX gene mutation has been proposed. The healthcare course relating to such patients has not been thoroughly defined in terms of implementation and is affected by regional organizational approaches. Implementing specific healthcare courses for such patients may provide a model for treating other patients with short stature and rare diseases with GH.

Improved molecular diagnostics of idiopathic short stature and allied disorders: quantitative polymerase chain reaction-based copy number profiling of SHOX and pseudoautosomal region 1

CONTEXT

Short stature has an incidence of three in 100 in children. Reliable molecular genetic testing may be crucial in the context of beneficial disease management. Deletions spanning or surrounding the SHOX gene account for a significant proportion of patients with idiopathic short stature (ISS) and allied disorders, such as Leri-Weill dyschondrosteosis.

OBJECTIVE

Several shortcomings of current strategies for copy number profiling of the SHOX region prompted us to develop an improved test for molecular diagnostics of the SHOX region.

DESIGN AND RESULTS

We introduced a quantitative PCR (qPCR)-based copy number profiling test, consisting of 11 amplicons targeting clinically relevant regions, i.e. the SHOX gene and regulatory regions. To ensure an optimal sensitivity and specificity, this test was validated in 32 controls and 18 probands with previously identified copy number changes. In addition, 152 probands with SHOX-associated phenotypes were screened, revealing 10 novel copy number changes.

CONCLUSION

This highly validated qPCR test supersedes other approaches for copy number screening of the SHOX region in terms of reliability, accuracy, and cost efficiency. In addition, another strong point is the fact that it can be easily implemented in any standard equipped molecular laboratory. Our qPCR-based test is highly recommended for molecular diagnostics of idiopathic short stature and allied disorders.

Approach to the patient with Turner syndrome

Turner syndrome (TS) occurs in about 1:4000 live births and describes females with a broad constellation of problems associated with loss of an entire sex chromosome or a portion of the X chromosome containing the tip of its short arm. TS is associated with an astounding array of potential abnormalities, most of them thought to be caused by haploinsufficiency of genes that are normally expressed by both X chromosomes. A health care checklist is provided that suggests screening tests at specific ages and intervals for problems such as strabismus, hearing loss, and autoimmune thyroid disease. Four areas of major concern in TS are discussed: growth failure, cardiovascular disease, gonadal failure, and learning disabilities. GH therapy should generally begin as soon as growth failure occurs, allowing for rapid normalization of height. Cardiac imaging, preferably magnetic resonance imaging, should be performed at diagnosis and repeated at 5- to 10-yr intervals to assess for congenital heart abnormalities and the emergence of aortic dilatation, a precursor to aortic dissection. Hypertension should be aggressively treated. For those with gonadal dysgenesis, hormonal replacement therapy should begin at a normal pubertal age and be continued until the age of 50 yr. Transdermal estradiol provides the most physiological replacement. Finally, nonverbal learning disabilities marked by deficits in visual-spatial-organizational skills, complex psychomotor skills, and social skills are common in TS. Neuropsychological testing should be routine and families given support in obtaining appropriate therapy, including special accommodations at school.

Effectiveness of the combined recombinant human growth hormone and gonadotropin-releasing hormone analog therapy in pubertal patients with short stature due to SHOX deficiency

CONTEXT

Isolated heterozygous SHOX defects are the most frequent monogenic cause of short stature, and combined therapy with recombinant human GH (rhGH) and GnRH analog (GnRHa) in pubertal patients has been suggested, but there are no data on final height.

OBJECTIVE

The aim of the study was to analyze adult height after rhGH and GnRHa therapy in patients with SHOX haploinsufficiency.

PATIENTS

Ten peripubertal patients with isolated SHOX defects participated in the study.

INTERVENTION

Five patients were followed without treatment, and five were treated with rhGH (50 mug/kg/d) and depot leuprolide acetate (3.75 mg/month).

MAIN OUTCOME MEASURES

Adult height sd score (SDS) was measured.

RESULTS

All patients followed without treatment had marked downward growth shift during puberty (height SDS, -1.2 +/- 0.7 at 11.4 +/- 1.4 yr; adult height SDS, -2.5 +/- 0.5). Conversely, four of five patients treated with rhGH for 2 to 4.9 yr associated to GnRHa for 1.4 to 5.8 yr improved their height SDS from -2.3 +/- 1.3 at 11.8 +/- 2.1 yr to a final height SDS of -1.7 +/- 1.6. The difference between the mean height SDS at the first evaluation and final height SDS was statistically significant in nontreated vs. treated patients (mean height SDS change, -1.2 +/- 0.4 vs. 0.6 +/- 0.4, respectively; P <0.001).

CONCLUSION

A gain in adult height of patients with isolated SHOX defects treated with combined rhGH and GnRHa therapy was demonstrated for the first time, supporting this treatment for children with SHOX defects who have just started puberty to avoid the loss of growth potential observed in these patients during puberty.

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.

Deletion of Xpter encompassing the SHOX gene and PAR1 region in familial patients with Leri-Weill Dyschondrosteosis syndrome

Heterozygote deletions or mutations of pseudoautosomal 1 region (PAR1) encompassing the short stature homeobox-containing (SHOX) gene cause Leri-Weill Dyschondrosteosis (LWD), which is a dominantly inherited osteochondroplasia characterized by short stature with mesomelic shortening of the upper and lower limbs and Madelung deformity of the wrists. SHOX is expressed by both sex chromosomes in males and females and plays an important role in bone growth and development. Clinically, the LWD expression is variable and more severe in females than males due to sex differences in oestrogen levels. Here, we report two familial cases of LWD with a large Xp terminal deletion (approximately 943 kb) of distal PAR1 encompassing the SHOX gene. In addition, the proband had mental retardation which appeared to be from recessive inheritance in the family.

[Bone dysplasia with short limb]

We described the condition of the disease, clinical appearance, X-rays appearance, orthopaedic problems about Achondroplasia, Pseudoachondroplasia, Metaphyseal Chondrodysplasia (Schmid type) , Mesomelic dysplasia (Dyschondrosteosis) as a representative bone dysplasia who present a short stature with short limbs. Clinical features are almost evident at birth in the patient with Achondroplasia. However, in other cases, there is no specific finding on clinically and radiologically at birth. Clinical and radiological findings develop slowly from period for childhood. It is considered that the diagnosis is not difficult since each of them have characteristic clinical features and X-rays views, only if examining them carefully. Correct and rapid diagnosis would be important for having a good relationship with patients.

The novel human SHOX allelic variant database

Short stature due to SHOX deficiency represents the most commonly known form of growth failure, with a frequency greater than 1:1,000 in the Caucasian population. As many different mutations can cause SHOX haploinsufficiency, a comprehensive collection of gene variants represents an essential tool to distinguish between functional variants and polymorphisms. We have created a novel and widely extended SHOX database using the "LOVD in a box-solution." This database contains not only a larger amount of mutation data (140 novel mutations were added), but also reports on phenotypic consequences, mode of inheritance, and ethnic origin, as well as on functional consequences of mutations investigated. In addition, the database now includes non-disease-related polymorphisms to enable researchers to evaluate their diagnostic findings. The database (Available at: http://hyg-serv-01.hyg.uni-heidelberg.de/lovd/index.php?select_db=SHOX; Last accessed: 12 April 2007) contains all presently known 199 intragenic mutations (SNPs as well as small deletions and insertions), 126 of which are unique. The remote user is able to search the data and to submit new mutations into the database. Furthermore, it includes general information about the SHOX gene via links to other resources such as MIM, GDB, HGMD, and HAPMAP, as well as websites of Short Stature Associations.