Short Stature Homeobox-containing Research Articles

Combined achondroplasia and short stature homeobox-containing (SHOX) gene deletion in a Danish infant

Short stature or shortening of the limbs can be the result of a variety of genetic variants. Achondroplasia is the most common cause of disproportionate short stature and is caused by pathogenic variants in the fibroblast growth factor receptor 3 gene (FGFR3).Short stature homeobox (SHOX) deficiency is caused by loss or defects of the SHOX gene or its enhancer region. It is associated with a spectrum of phenotypes ranging from normal stature to Léri-Weill dyschondrosteosis characterized by mesomelia and short stature or the more severe Langer mesomelic dysplasia in case of biallelic SHOX deficiency.Little is known about the interactions and phenotypic consequences of achondroplasia in combination with SHOX deficiency, as the literature on this subject is scarce, and no genetically confirmed clinical reports exist. We present the clinical findings in an infant girl with concurrent achondroplasia and SHOX deficiency. We conclude that the clinical findings in infancy are phenotypically compatible with achondroplasia, with no features of the SHOX deficiency evident. This may change over time, as some features of SHOX deficiency only become evident later in life.

Shortened fetal long bones: A notable intrauterine phenotypic feature in SHOX-associated skeletal dysplasia.

To explore the intrauterine phenotypic spectrum of short stature homeobox-containing (SHOX) gene-associated skeletal dysplasia and provide genetic counseling at-risk pregnancies. We analyzed the fetuses with SHOX-microdeletions identified by single nucleotide polymorphism (SNP)-array. The intrauterine phenotypes and outcomes were further elaborated. Nine fetuses carrying a single SHOX-microdeletion were reported, with deletion sizes ranging from 0.134 to 1.35 Mb. Shortened long bones were observed in all fetuses, varying from -2.0 standard deviation (SD) to -5.3 SD. Moreover, all cases had a femur length/foot ratio less than 0.87 and a femur/abdominal circumference ratio greater than 0.16, suggesting that non-lethal skeletal dysplasia may be involved. Two fetuses showed intrauterine growth restriction, and two had nasal bone hypoplasia. Prenatal ultrasonography did not reveal other obvious anomalies, including the Madelung deformity. Five microdeletions were inherited and one was de novo. Five terminations and four newborns were recorded. Two newborns had normal stature, and two were short-statured (height <3rd percentile), with one having inflexible wrists. SHOX haploinsufficiency may manifest with shortened fetal long bones. The combination of history taking, prenatal ultrasonography, and SNP-array can prompt early prenatal diagnosis and timely postnatal treatment of SHOX-associated skeletal dysplasia.

Clinical impact of variants in non-coding regions of SHOX - Current knowledge.

The short stature homeobox-containing (SHOX) is the most frequently analysed gene in patients classified as short stature patients (ISS) or diagnosed with Leri-Weill dyschondrosteosis (LWD), Langer mesomelic dysplasia (LMD), or Madelung deformity (MD). However, clinical testing of this gene focuses primarily on single nucleotide variants (SNV) in its coding sequences and copy number variants (CNV) overlapping SHOX gene. This review summarizes the clinical impact of variants in noncoding regions of SHOX. RECENT FINDINGS: CNV extending exclusively into the regulatory elements (i.e., not interrupting the coding sequence) are found more frequently in downstream regulatory elements of SHOX. Further, duplications are more frequent than deletions. Interestingly, downstream duplications are more common than deletions in patients with ISS or LWD but no such differences exist for upstream CNV. Moreover, the presence of specific CNVs in the patient population suggests the involvement of additional unknown factors. Some of its intronic variants, notably NM_000451.3(SHOX):c.-9delG and c.-65C>A in the 5'UTR, have unclear clinical roles. However, these intronic SNV may increase the probability that other CNV will arise de novo in the SHOX gene based on homologous recombination or incorrect splicing of mRNA. SUMMARY: This review highlights the clinical impact of noncoding changes in the SHOX gene and the need to apply new technologies and genotype-phenotype correlation in their analysis.

EP342: Clinical testing of SHOX gene for SHOX deficiency disorders

Haploinsufficiency of the short stature homeobox-containing (SHOX) gene causes a range of disorders from the milder phenotype of isolated short stature to the more severe Leri-Weill dyschondrosteosis (LWD). The SHOX gene maps to the pseudoautosomal region of the sex chromosomes, allowing for pseudoautosomal inheritance. Pathogenic SHOX variants on one allele cause LWD and familial short stature, while pathogenic variants on both alleles cause Langer mesomelic dysplasia (LMD). Deletions and duplications of the SHOX coding region, or the enhancer element(s) upstream or downstream of SHOX gene are representative of 80-90% of SHOX disorders, while the rest of the patients were identified to have pathogenic sequence variants.

Detection of SHOX gene deletions in Egyptian children with idiopathic short stature using FISH

The short stature homeobox-containing (SHOX) gene, mapped on the pseudoautosomal region of the X and Y chromosomes, strongly affects human height. Therefore, SHOX haploinsufficiency has been reported to cause idiopathic short stature (ISS) and the short stature seen in patients with Turner's syndrome, Leri-Weill dyschondrosteosis, and Langer mesomelic dysplasia. SHOX deletions are responsible for approximately 80% of isolated haploinsufficiency. Aiming to evaluate the prevalence of SHOX gene deletions in the Egyptian patients with unexplained short stature, the present study used FISH analysis to investigate SHOX deletions in 25 patients with ISS. Despite the tiny sample size and the limitations of the used analysis technique, our findings emphasize the importance of including SHOX mutation analysis in the genetic workup of ISS cases. Furthermore, this study could not confirm a correlation of SHOX deletions with any specific clinical feature or an anthropometric measurement.

SAT-303 Combined Treatment of Gonadotropin Releasing Hormone Agonist and Recombinant Human Growth Hormone in Cental Precocious Puberty Patient with Underlying Leri Weill Dyschondrosteosis

Leri-Weill dyschondrosteosis (LWD) is a rare genetic disorder of bony growth characterized by abnormal shortening of the forearms and lower legs, abnormal misalignment of the wrist (Madelung deformity), and associated short stature. As a result of shortened leg bones, LMD patients typically have short stature. Additional symptoms and severity can vary greatly from one person to another, even among members of the same family. LWD is caused by a heterozygous mutation in the short stature homeobox-containing (SHOX) gene or its regulatory elements (enhancers) located on the pseudoautosomal region 1 (PAR1) of the sex chromosomes. There are a number of reports about GH-treated SHOX-deficient patients such as LMD, idiopathic short stature, and Turner syndrome, however, in this report, we would like to introduce a rare case with underlying LWD and central precocious puberty, who was treated by combined therapy of gonadotropin releasing hormone (GnRH) agonist and recombinant human growth hormone (rhGH). A 8 years and 4 months old girl visited our clinic for short stature and breast development of Tanner stage 2. In physical examination, her height was 117 cm (<3rd percentile), weight was 22 kg (13th percentile), and BMI was 16.07 kg/m2. Her father's and mother's height was 165cm and 162 cm, respectively, and her midparental height was calculated as 157cm. There were no specific findings in family history. She showed high arched palate and disproportion of limbs. In radiologic studies, the patient showed Madelung deformity of both forearms and functional scoliosis, and her bone age was assessed to be 9 years 7 months by TW3 method. In laboratory findings, LHRH stimulation test showed a pubertal response (peak LH level: 12.4 IU/L after 30mins). Abdominopelvic ultrasonography revealed her uterus and ovary both as pubertal status and no other abnormal findings were noted. Therefore, we diagnosed her as LWD and sexual precocity, and the results of the molecular genetics test confirmed the suspicion of LWD. The combination treatment of GnRH agonist and rhGH was started to improve the final adult height for the patient with early onset pubescence and short stature. After 3 years and 7 months of treatment, her height was 146cm and additional growth gain was 29cm. Secondary sexual characteristics proceeded to Tanner stage IV in normal order, and menarche occured at 13 years old. No adverse event was observed. After 6 months of completion of treatment, her height was 150 cm which was thought to be near adult height. In conclusion, LMD patients typically have short stature and it has been known that rhGH treatment is effective for growth promotion in these patients. However, clinicians should be aware of the possibility of LWD and concominant diagnosis of precocious puberty, which could lessen the predicted adult height, and in that case, combined therapy of GnRH agonist and rhGH can be helpful to improve the final height.

SHOX gene deletion screening by FISH in children with short stature and Madelung deformity and their characteristics.

Background The short stature homeobox-containing (SHOX) gene strongly affects height. Therefore, a better understanding of SHOX haploinsufficiency could be advantageous to early diagnosis and treatment. We investigated the rate of SHOX haploinsufficiency in patients of short stature and documented their anthropometric measurements. Methods Between 2010 and 2017, we evaluated 86 patients (70 females, 16 males; age 4.3-18 years) with clinical diagnoses of short stature and Madelung deformity (MD). Clinical abnormalities are presented for patients with MD with and without SHOX haploinsufficiency as determined by fluorescence in situ hybridisation (FISH). Results According to our inclusion criteria, 78 of 86 patients (70 females, 16 males) had short stature (height <-2.5 standard deviation [SD]) and a family history suggestive of short stature. Eight patients had short stature, a family history suggestive of short stature and MD. MD was obvious in eight children in radiographic examinations. Although five of these had no deletion of SHOX, three had deletion of this gene. The deletion detection rate was 37.5% in the individuals with short stature and MD, i.e. Leri-Weill dyschondrosteosis syndrome (LWS), whilst no deletions were detected in the individuals with only short stature. One individual responded well to growth hormone (GH) treatment for the first 2 years but then developed an intolerance with persistently elevated insulin-like growth factor-1 (IGF-1) levels. Conclusions As we likely missed cases due to our methodology, the routine analysis for SHOX screening should be firstly multiplex ligation-dependent probe amplification (MLPA). The incidence of MD may have been higher in the cohort if X-rays were performed in all individuals. GH treatment was not well tolerated in one case due to persistently elevated IGF-1 levels, and long-term evaluations of patients with SHOX deficiency are required.

Microduplications at the pseudoautosomal SHOX locus in autism spectrum disorders and related neurodevelopmental conditions

BackgroundThe pseudoautosomal short stature homeobox-containing (SHOX) gene encodes a homeodomain transcription factor involved in cell-cycle and growth regulation. SHOX/SHOX enhancers deletions cause short stature and skeletal abnormalities in a female-dominant...

Effects of Growth Hormone on Bone.

Describe the effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) on the skeleton. The GH and IGF-1 axis has pleiotropic effects on the skeleton throughout the lifespan by influencing bone formation and resorption. GH deficiency leads to decreased bone turnover, delayed statural growth in children, low bone mass, and increased fracture risk in adults. GH replacement improves adult stature in GH deficient children, increases bone mineral density (BMD) in adults, and helps to optimize peak bone acquisition in patients, during the transition from adolescence to adulthood, who have persistent GH deficiency. Observational studies suggest that GH replacement may mitigate the excessive fracture risk associated with GH deficiency. Acromegaly, a state of GH and IGF-1 excess, is associated with increased bone turnover and decreased BMD in the lumbar spine observed in some studies, particularly in patients with hypogonadism. In addition, patients with acromegaly appear to be at an increased risk of morphometric-vertebral fractures, especially in the presence of active disease or concurrent hypogonadism. GH therapy also has beneficial effects on statural growth in several conditions characterized by GH insensitivity, including chronic renal failure, Turner syndrome, Prader-Willi syndrome, postnatal growth delay in patients with intrauterine growth retardation who do not demonstrate catchup growth, idiopathic short stature, short stature homeobox-containing (SHOX) gene mutations, and Noonan syndrome. GH and IGF-1 have important roles in skeletal physiology, and GH has an important therapeutic role in both GH deficiency and insensitivity states.

Radiological Features in Patients with Short Stature Homeobox-Containing (SHOX) Gene Deficiency and Turner Syndrome before and after 2 Years of GH Treatment

Background/Aims: The short stature homeobox-containing (SHOX) gene is one of many genes that regulate longitudinal growth. The SHOX deficiency (SHOX-D) phenotype, caused by intragenic or regulatory region defects, ranges from normal stature to mesomelic skeletal dysplasia. We investigated differences in radiological anomalies between patients with SHOX-D and Turner syndrome (TS) and the effect of 2 years of growth hormone (GH) treatment on these anomalies. Methods: Left hand/wrist, forearm and lower leg radiographs were assessed at baseline and after 2 years in children with genetically confirmed SHOX-D (GH-treated and untreated groups) and TS (GH-treated) in a randomised, controlled, multinational study. Results: Radiological anomalies of hand, wrist and forearm were common in SHOX-D and TS. Radial bowing appeared more prevalent in SHOX-D, while lower leg anomalies were more common in TS. There were no significant differences in radiological findings between GH-treated and untreated patients with SHOX-D after 2 years. Conclusion: GH treatment had no systematic effect on skeletal findings in SHOX-D, based on limited radiological differences between the GH-treated and untreated groups at 2 years. Bone age radiographs allow assessment of radiological signs indicating a potential diagnosis of SHOX-D and may lead to earlier genetic confirmation and initiation of GH therapy.

Structural and numerical changes of chromosome X in patients with esophageal atresia

Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) is a relatively common birth defect often associated with additional congenital anomalies such as vertebral, anal, cardiovascular, renal and limb defects, the so-called VACTERL association. Yet, little is known about the causal genetic factors. Rare case reports of gastrointestinal anomalies in children with triple X syndrome prompted us to survey the incidence of structural and numerical changes of chromosome X in patients with EA/TEF. All available (n=269) karyotypes of our large (321) EA/TEF patient cohort were evaluated for X-chromosome anomalies. If sufficient DNA material was available, we determined genome-wide copy number profiles with SNP array and identified subtelomeric aberrations on the difficult to profile PAR1 region using telomere-multiplex ligation-dependent probe amplification. In addition, we investigated X-chromosome inactivation (XCI) patterns and mode of inheritance of detected aberrations in selected patients. Three EA/TEF patients had an additional maternally inherited X chromosome. These three female patients had normal random XCI patterns. Two male EA/TEF patients had small inherited duplications of the XY-linked SHOX (Short stature HOmeoboX-containing) locus. Patients were small for gestational age at birth (<P5) and had additional, mostly VACTERL associated, anomalies. Triple X syndrome is rarely described in patients with EA/TEF and no duplications of the SHOX gene were reported so far in these patients. As normal patterns of XCI were seen, overexpression of X-linked genes that escape XCI, such as the SHOX gene, could be pathogenic by disturbing developmental pathways.

Valutazione di efficienza nella somministrazione dell’ormone della crescita (GH)

Treatment with growth hormone (somatropin) is effective in six different medical conditions: growth hormone deficiency (GHD), Turner syndrome (TS), growth retardation in children born small for gestational age (SGA), Prader-Willi syndrome (PWS), growth retardation due to chronic renal insufficiency (CRI), growth retardation associated with a deficiency of the gene SHOX (Short Stature HOmeoboXContaining gene). The treatment proved to be also effective in adults who have an impaired growth hormone (acquired in adulthood or childhood).The growth hormone (GH) is generally cost effective and, therefore, is usually reimbursed by public health services. In financial terms, GH is a major cost item for health systems. According to the Report OSMED 2010, GH ranks first in Italy between systemic hormonal preparations, excluding sex hormones, distributed by public system, with an annual value of approximately € 88 million (+ 12.7% compared to 2009).Considering the increasing need to control pharmaceutical expenditure, there is a strong interest for the efficient supply of the hormone by the regional health service. From this point of view, the comparison of the specialties on the market is normally carried out on the basis of the cost per mg; this approach, also used in the main studies of cost-effectiveness, is derived from a logic of cost minimization, but it may still be distorting, not taking into account the efficiency of devices used for the administration of the hormone.The proposed analysis verifies the efficiency of different available devices, evaluating the potential waste of product, depending both on the device used and on the characteristics of the population exposed to the treatment.Only in the case of single-dose and disposable formulations is theoretically possible to have zero waste and thus an equivalence between the actual cost of the treatment and the price charged. In other cases, the inefficiency causes a deviation between the actual cost and price. In the latter cases, since the theoretical amount of the population exposed to the treatment, it is estimated that the total share of potentially unused product can vary between 208,000 mg / year to 750,000 mg / year, depending on the device used. In particular, there is an actual average cost of treatment ranging between +9.9% and +11.4% of the ex-factory price; depending on the different doses and even between the different devices, the difference between the actual price and the theoretical price varies from a minimum of +6.9% and a maximum of +18.7%.

Impaired GH Secretion in Patients with SHOX Deficiency and Efficacy of Recombinant Human GH Therapy

Background/Aims: Mutations of the short stature homeobox-containing (SHOX) gene on the pseudoautosomal region of the sex chromosomes cause short stature. GH treatment has been recently proposed to improve height in short patients with SHOX deficiency. The aim of this study was to evaluate GH secretion and analyze growth and safety of recombinant human GH (rhGH) therapy in short children and adolescents with SHOX deficiency. Patients and Design: We studied 16 patients (10 females; 9.7 ± 2.9 years old; height –2.46 ± 0.82 standard deviation score, SDS) with SHOX deficiency. All subjects underwent auxological evaluations, biochemical investigations, and were treated with rhGH (0.273 ± 0.053 mg/kg/week). Results: Impaired GH secretion was present in 37.5% of the studied subjects. Comparing baseline data with those at the last visit, we found that rhGH treatment improved growth velocity SDS (from –1.03 ± 1.44 to 2.77 ± 1.95; p = 0.001), height SDS (from –2.41 ± 0.71 to –1.81 ± 0.87; p < 0.001), and IGF-1 values (from –0.57 ± 1.23 to 0.63 ± 1.63 SDS, p = 0.010) without affecting body mass index SDS. Height SDS measured at the last visit was significantly correlated with chronological age (r = –0.618, p = 0.032), bone age (r = –0.582, p = 0.047) and height SDS (r = 0.938, p < 0.001) at the beginning of treatment. No adverse events were reported on rhGH therapy which was never discontinued. Conclusion: These data showed that impaired GH secretion is not uncommon in SHOX deficiency subjects, and that rhGH therapy may be effective in increasing height in most of these patients independent of their GH secretory status, without causing any adverse events of concern.

Short stature homeoboxcontaining gene and idiopathic short stature

The term idiopathic short stature (ISS) refers to patients who are short due to various unknown reasons. Although it is clear that multiple factors contribute to final height, genetic factors play a crucial role. Mutations of a human homeobox gene, short stature homeobox-containing (SHOX) gene, have been shown to be associated with the short stature phenotype in patients with Turner syndrome, most patients with Leri-Weill dyschondrosteosis and some cases of ISS. The prevalence of SHOX anomalies in subjects previously recognized as having ISS has been estimated at 2.4% in a large series of ISS individuals. This review focuses on the functional properties of the SHOX gene and its linkage to ISS.

The Human Pseudoautosomal Region (PAR): Origin, Function and Future

The pseudoautosomal regions (PAR1 and PAR2) of the human X and Y chromosomes pair and recombine during meiosis. Thus genes in this region are not inherited in a strictly sex-linked fashion. PAR1 is located at the terminal region of the short arms and PAR2 at the tips of the long arms of these chromosomes. To date, 24 genes have been assigned to the PAR1 region. Half of these have a known function. In contrast, so far only 4 genes have been discovered in the PAR2 region. Deletion of the PAR1 region results in failure of pairing and male sterility. The gene SHOX (short stature homeobox-containing) resides in PAR1. SHOX haploinsufficiency contributes to certain features in Turner syndrome as well as the characteristics of Leri-Weill dyschondrosteosis. Only two of the human PAR1 genes have mouse homologues. These do not, however, reside in the mouse PAR1 region but are autosomal. The PAR regions seem to be relics of differential additions, losses, rearrangements and degradation of the X and Y chromosome in different mammalian lineages. Marsupials have three homologues of human PAR1 genes in their autosomes, although, in contrast to mouse, do not have a PAR region at all. The disappearance of PAR from other species seems likely and this region will only be rescued by the addition of genes to both X and Y, as has occurred already in lemmings. The present review summarizes the current understanding of the evolution of PAR and provides up-to-date information about individual genes residing in this region.

Different skeletal phenotypes in a mother and two daughters with short stature homeobox-containing haploinsufficiency.

Haploinsufficiency of the short stature homeobox-containing (SHOX) gene causes Turner skeletal features such as short metacarpals, cubitus valgus, and Madelung deformity. We report the clinical findings of a Japanese family consisting of two daughters with SHOX haploinsufficiency (46, X, del(X) (p.22.3)) and their mother with 45,X [9]/ 46, X, del(X) (p22.3) [11] karyotype. Physical and auxological examinations revealed a mesomelic appearance, cubitus valgus, a short neck and short stature in the daughters, but on the other hand, only a short neck and short stature in the mother. Radiological studies indicated markedly curved radii in the daughters, but only mild curvature of the radii in the mother. Regular menstruation had taken place since the age of 12 yr in the elder daughter, but the mother had irregular menstruation and she had received fertility treatment for pregnancy. The different skeletal phenotypes of the mother and her daughters with SHOX haploinsufficiency might be due to the mild gonadal estrogen deficiency found in the mother, which was caused by mosaic Turner syndrome, and the phenotypic variability of SHOX haploinsufficiency.

Quantitative Real-Time Polymerase Chain Reaction (RQ-PCR) for the Rapid Detection of SHOX Haploinsufficiency in Leri-Weill Syndrome

The short stature homeobox-containing (SHOX) gene, found on the human sex chromosomes, has a role in bone growth and height determination. Haploinsufficiency of the SHOX gene is believed to be responsible for poor growth such as that observed in ther Leri-Weill syndrome (LWS). This is the first report of the study of SHOX gene copy number by the technique of quantitative real-time polymerase chain reaction (RQ-PCR) in 9 patients with LWS. Only 7 patients (78%) of LWS had one copy of the SHOX gene deleted, but 2 patients (12%) have neither a single copy gene deletion nor point mutation after direct sequencing of all 7 exons. Although the majority of patients with LWS in this study have SHOX gene haploinsufficiency, there are some patients with both copies of the SHOX gene intact with absence of any point mutations in the coding region. This may be due to abnormalities in the upstream promoter, or to the effect of other candidate gene mutations. RQ-PCR is a faster and cheaper method of studying SHOX sing-copy deletions compared with the conventional fluorescence in situ hybridization (FISH), and is recommended for the detection of SHOX gene haploinsufficiency.

Short stature and turner skeletal features in an 11-year-old boy with a ring y chromosome missing the short stature homeobox containing gene.

We report on an 11-yr-old boy with short stature and Turner skeletal features. Chromosome analysis revealed a 46,X,r(Y)(p11.3q11.2) karyotype, and FISH analysis showed loss of the Short stature homeobox containing gene (SHOX) from the ring Y chromosome. The results are consistent with the association of SHOX haploinsufficiency with short stature and Turner skeletal features, and suggest the importance of SHOX analysis in boys with Turner-like skeletal phenotype.

Longitudinal Observation of a Patient with Leri-Weill Dyschondrosteosis and SHOX Haploinsufficiency.

Haploinsufficiency of the short stature homeobox-containing (SHOX) gene causes Turner skeletal features, a certain proportion of idiopathic short stature and Leri-Weill dyschondrosteosis (LWD). Here we report a Japanese female with LWD. Her physical growth, skeletal deformity, and endocrine status were recorded longitudinally. She exhibited a constant growth rate (average + 6.2 cm/yr) from 6 to 9 yr old, followed by a downward shift at 10 yr old. Her final height was 135 cm (–4.4 SD for an adult female) and weight was 50.5 kg (–0.3 SD) at 12 yr and 10 mo old. Mesomelia and cubitus valgus were noticed from 2 yr old, and metaphyseal lucency and epiphyseal hypoplasia of the medial side of the distal radius were detected at 6 yr old. Madelung deformity was obvious at 10 yr old, when menarche occurred. Fluorescence in situ hybridization (FISH) analysis demonstrated a single copy of the SHOX gene. The short stature of the patient was thought to be exaggerated by the combination of SHOX haploinsufficiency and relatively early puberty.

Phenotypes Associated with SHOX Deficiency.

Leri-Weill dyschondrosteosis (LWD) (MIM 127300) is a dominantly inherited skeletal dysplasia characterized phenotypically by Madelung wrist deformity, mesomelia, and short stature. LWD can now be defined genetically by haploinsufficiency of the SHOX (short stature homeobox-containing) gene. We have studied 21 LWD families (43 affected LWD subjects, including 32 females and 11 males, ages 3-56 yr) with confirmed SHOX abnormalities. We investigated the relationship between SHOX mutations, height deficit, and Madelung deformity to determine the contribution of SHOX haploinsufficiency to the LWD and Turner syndrome (TS) phenotypes. Also, we examined the effects of age, gender, and female puberty (estrogen) on the LWD phenotype. SHOX deletions were present in affected individuals from 17 families (81%), and point mutations were detected in 4 families (19%). In the LWD subjects, height deficits ranged from -4.6 to +0.6 SD (mean +/- SD = -2.2 +/- 1.0). There were no statistically significant effects of age, gender, pubertal status, or parental origin of SHOX mutations on height z-score. The height deficit in LWD is approximately two thirds that of TS. Madelung deformity was present in 74% of LWD children and adults and was more frequent and severe in females than males. The prevalence of the Madelung deformity was higher in the LWD vs. a TS population. The prevalence of increased carrying angle, high arched palate, and scoliosis was similar in the two populations. In conclusion, SHOX deletions or mutations accounted for all of our LWD cases. SHOX haploinsufficiency accounts for most, but not all, of the TS height deficit. The LWD phenotype shows some gender- and age-related differences.