Utility of CYP2D6 copy number variants as prognostic biomarker in localized anal squamous cell carcinoma.

BACKGROUND: Anal squamous cell carcinoma (ASCC) is an infrequent tumor whose treatment has not changed since the 1970s. The aim of this study is the identification of biomarkers allowing personalized treatments and improvement of therapeutic outcomes. METHODS: Forty-six paraffin tumor samples from ASCC patients were analyzed by whole-exome sequencing. Copy number variants (CNVs) were identified and their relation to disease-free survival (DFS) was studied and validated in an independent retrospective cohort of 101 ASCC patients from the Multidisciplinary Spanish Digestive Cancer Group (GEMCAD). GEMCAD cohort proteomics allowed assessing the biological features of these tumors. RESULTS: On the discovery cohort, the median age was 61 years old, 50% were males, stages I/II/III: 3 (7%)/16 (35%)/27 (58%), respectively, median DFS was 33 months, and overall survival was 45 months. Twenty-nine genes whose duplication was related to DFS were identified. The most representative was duplications of the CYP2D locus, including CYP2D6, CYP2D7P, and CYP2D8P genes. Patients with CYP2D6 CNV had worse DFS at 5 years than those with two CYP2D6 copies (21% vs. 84%; p < .0002, hazard ratio [HR], 5.8; 95% confidence interval [CI], 2.7-24.9). In the GEMCAD validation cohort, patients with CYP2D6 CNV also had worse DFS at 5 years (56% vs. 87%; p = .02, HR = 3.6; 95% CI, 1.1-5.7). Mitochondria and mitochondrial cell-cycle proteins were overexpressed in patients with CYP2D6 CNV. CONCLUSIONS: Tumor CYP2D6 CNV identified patients with a significantly worse DFS at 5 years among localized ASCC patients treated with 5-fluorouracil, mitomycin C, and radiotherapy. Proteomics pointed out mitochondria and mitochondrial cell-cycle genes as possible therapeutic targets for these high-risk patients. PLAIN LANGUAGE SUMMARY: Anal squamous cell carcinoma is an infrequent tumor whose treatment has not been changed since the 1970s. However, disease-free survival in late staged tumors is between 40% and 70%. The presence of an alteration in the number of copies of CYP2D6 gene is a biomarker of worse disease-free survival. The analysis of the proteins in these high-risk patients pointed out mitochondria and mitochondrial cell-cycle genes as possible therapeutic targets. Therefore, the determination of the number of copies of CYP2D6 allows the identification of anal squamous carcinoma patients with a high-risk of relapse that could be redirected to a clinical trial. Additionally, this study may be useful to suggest new treatment strategies to increase current therapy efficacy.

The portrayal of dwarfism without skeletal dysplasia in art: Proportionate short stature due to growth hormone deficiency and other disorders.

In this article, we analyze several works of art which portray individuals with short stature ("dwarfism"). We have focused on eight individuals who we believe have short stature due to growth hormone deficiency (GHD) or closely related disorders, rather than skeletal dysplasia. We discuss them individually, suggest the potential diagnosis, review the characteristics of their life and personal history, and briefly outline the artistic framework in which these works of art were created. This work is a posthumous tribute to the people with short stature portrayed in these works of art, who likely experienced harassment and inappropriate treatment by others and called by derogatory names. We have tried to acknowledge their identities with the respect they deserve.

Loss of function BMP4 mutation supports the implication of the BMP/TGF-ß pathway in the etiology of combined pituitary hormone deficiency.

Despite BMP4 signaling being critical to Rathke's pouch induction and maintenance during early stages of pituitary development, its implication in the etiology of combined pituitary hormone deficiency (CPHD) and other clinical presentations of congenital hypopituitarism has not yet been definitely demonstrated. We report here the first CPHD patient with a de novo pathogenic loss-of-function variant in BMP4. A 6-year-old boy, with macrocephaly, myopia/astigmatism, mild psychomotor retardation, anterior pituitary hypoplasia and ectopic posterior pituitary, clinically diagnosed with growth hormone deficiency, and central hypothyroidism, was referred for genetic analysis of CPHD. Targeted NGS analysis with a custom panel (n = 310 genes) identified a novel heterozygous de novo nonsense variant, NM_001202.5:c.794G > A, p.(Trp265*) in BMP4, which introduces a premature stop codon in the BMP4 pro-domain, impairing the transcription of the TGF-ß mature peptide domain. Additional relevant variants in other genes implicated in pituitary development signaling pathways such as SMAD4 and E2F4 (BMP/TGF-pathway), ALMS1 (NOTCH-pathway), and TSHZ1 (Prokineticin-pathway), were also identified. Our results support the implication of the BMP/TGF-ß signaling pathway in the etiology of CPHD and suggest that oligogenic contribution of additional inherited variants may modify the phenotypic expressivity of BMP4 pathogenic variants.

Mutations in C-natriuretic peptide (NPPC): a novel cause of autosomal dominant short stature.

PurposeC-type natriuretic peptide (CNP) and its principal receptor, natriuretic peptide receptor B (NPR-B), have been shown to be important in skeletal development. CNP and NPR-B are encoded by natriuretic peptide precursor-C (NPPC) and natriuretic peptide receptor 2 (NPR2) genes, respectively. While NPR2 mutations have been described in patients with skeletal dysplasias and idiopathic short stature (ISS), and several Npr2 and Nppc skeletal dysplasia mouse models exist, no mutations in NPPC have been described in patients to date.MethodsNPPC was screened in 668 patients (357 with disproportionate short stature and 311 with autosomal dominant ISS) and 29 additional ISS families in an ongoing whole-exome sequencing study.ResultsTwo heterozygous NPPC mutations, located in the highly conserved CNP ring, were identified. Both showed significant reductions in cyclic guanosine monophosphate synthesis, confirming their pathogenicity. Interestingly, one has been previously linked to skeletal abnormalities in the spontaneous Nppc mouse long-bone abnormality (lbab) mutant.ConclusionsOur results demonstrate, for the first time, that NPPC mutations cause autosomal dominant short stature in humans. The NPPC mutations cosegregated with a short stature and small hands phenotype. A CNP analog, which is currently in clinical trials for the treatment of achondroplasia, seems a promising therapeutic approach, since it directly replaces the defective protein.

Two novel POC1A mutations in the primordial dwarfism, SOFT syndrome: Clinical homogeneity but also unreported malformations.

Primordial dwarfism encompasses rare conditions characterized by severe intrauterine growth retardation and growth deficiency throughout life. Recently, three POC1A mutations have been reported in six families with the primordial dwarfism, SOFT syndrome (Short stature, Onychodysplasia, Facial dysmorphism, and hypoTrichosis). Using a custom-designed Next-generation sequencing skeletal dysplasia panel, we have identified two novel homozygous POC1A mutations in two individuals with primordial dwarfism. The severe growth retardation and the facial profiles are strikingly similar between our patients and those described previously. However, one of our patients was diagnosed with severe foramen magnum stenosis and subglottic tracheal stenosis, malformations not previously associated with this syndrome. Our findings confirm that POC1A mutations cause SOFT syndrome and that mutations in this gene should be considered in patients with severe pre- and postnatal short stature, symmetric shortening of long bones, triangular facies, sparse hair and short, thickened distal phalanges.

A new overgrowth syndrome is due to mutations in RNF125.

Overgrowth syndromes (OGS) are a group of disorders in which all parameters of growth and physical development are above the mean for age and sex. We evaluated a series of 270 families from the Spanish Overgrowth Syndrome Registry with no known OGS. We identified one de novo deletion and three missense mutations in RNF125 in six patients from four families with overgrowth, macrocephaly, intellectual disability, mild hydrocephaly, hypoglycemia, and inflammatory diseases resembling Sjögren syndrome. RNF125 encodes an E3 ubiquitin ligase and is a novel gene of OGS. Our studies of the RNF125 pathway point to upregulation of RIG-I-IPS1-MDA5 and/or disruption of the PI3K-AKT and interferon signaling pathways as the putative final effectors.

Genetic Findings in Short Turkish Children Born to Consanguineous Parents.

INTRODUCTION: The diagnostic yield of genetic analysis in the evaluation of children with short stature depends on associated clinical characteristics, but the additional effect of parental consanguinity has not been well documented. METHODS: This observational case series of 42 short children from 34 consanguineous families was collected by six referral centres of paediatric endocrinology (inclusion criteria: short stature and parental consanguinity). In 18 patients (12 families, group 1), the clinical features suggested a specific genetic defect in the growth hormone (GH) insulin-like growth factor I (IGF-I) axis, and a candidate gene approach was used. In others (group 2), a hypothesis-free approach was chosen (gene panels, microarray analysis, and whole exome sequencing) and further subdivided into 11 patients with severe short stature (height <-3.5 standard deviation score [SDS]) and microcephaly (head circumference <-3.0 SDS) (group 2a), 10 patients with syndromic short stature (group 2b), and 3 patients with nonspecific isolated GH deficiency (group 2c). RESULTS: In all 12 families from group 1, (likely) pathogenic variants were identified in GHR, IGFALS, GH1, and STAT5B. In 9/12 families from group 2a, variants were detected in PCNT, SMARCAL1, SRCAP, WDR4, and GHSR. In 5/9 families from group 2b, variants were found in TTC37, SCUBE3, NSD2, RABGAP1, and 17p13.3 microdeletions. In group 2c, no genetic cause was found. Homozygous, compound heterozygous, and heterozygous variants were found in 21, 1, and 4 patients, respectively. CONCLUSION: Genetic testing in short children from consanguineous parents has a high diagnostic yield, especially in cases of severe GH deficiency or insensitivity, microcephaly, and syndromic short stature.

SHOX interacts with the chondrogenic transcription factors SOX5 and SOX6 to activate the aggrecan enhancer.

SHOX (short stature homeobox-containing gene) encodes a transcription factor implicated in skeletal development. SHOX haploinsufficiency has been demonstrated in Leri-Weill dyschondrosteosis (LWD), a skeletal dysplasia associated with disproportionate short stature, as well as in a variable proportion of cases with idiopathic short stature (ISS). In order to gain insight into the SHOX signalling pathways, we performed a yeast two-hybrid screen to identify SHOX-interacting proteins. Two transcription factors, SOX5 and SOX6, were identified. Co-immunoprecipitation assays confirmed the existence of the SHOX-SOX5 and SHOX-SOX6 interactions in human cells, whereas immunohistochemical studies demonstrated the coexpression of these proteins in 18- and 32-week human fetal growth plates. The SHOX homeodomain and the SOX6 HMG domain were shown to be implicated in the SHOX-SOX6 interaction. Moreover, different SHOX missense mutations, identified in LWD and ISS patients, disrupted this interaction. The physiological importance of these interactions was investigated by studying the effect of SHOX on a transcriptional target of the SOX trio, Agc1, which encodes one of the main components of cartilage, aggrecan. Our results show that SHOX cooperates with SOX5/SOX6 and SOX9 in the activation of the upstream Agc1 enhancer and that SHOX mutations affect this activation. In conclusion, we have identified SOX5 and SOX6 as the first two SHOX-interacting proteins and have shown that this interaction regulates aggrecan expression, an essential factor in chondrogenesis and skeletal development.

Identification of the first recurrent PAR1 deletion in Léri-Weill dyschondrosteosis and idiopathic short stature reveals the presence of a novel SHOX enhancer.

BACKGROUND: SHOX, located in the pseudoautosomal region 1 (PAR1) of the sexual chromosomes, encodes a transcription factor implicated in human growth. Defects in SHOX or its enhancers have been observed in ∼60% of Leri-Weill dyschondrosteosis (LWD) patients, a skeletal dysplasia characterised by short stature and/or the characteristic Madelung deformity, and in 2-5% of idiopathic short stature (ISS). To identify the molecular defect in the remaining genetically undiagnosed LWD and ISS patients, this study screened previously unanalysed PAR1 regions in 124 LWD and 576 ISS probands. METHODS: PAR1 screening was undertaken by multiplex ligation dependent probe amplification (MLPA). Copy number alterations were subsequently confirmed and delimited by locus-specific custom-designed MLPA, array comparative genomic hybridisation (CGH) and breakpoint junction PCR/sequencing. RESULTS: A recurrent PAR1 deletion downstream of SHOX spanning 47543 bp with identical breakpoints was identified in 19 LWD (15.3%) and 11 ISS (1.9%) probands, from 30 unrelated families. Eight evolutionarily conserved regions (ECRs 1-8) identified within the deleted sequence were evaluated for SHOX regulatory activity by means of chromosome conformation capture (3C) in chicken embryo limbs and luciferase reporter assays in human U2OS osteosarcoma cells. The 3C assay indicated potential SHOX regulatory activity by ECR1, which was subsequently confirmed to act as a SHOX enhancer, operating in an orientation and position independent manner, in human U2OS cells. CONCLUSIONS: This study has identified the first recurrent PAR1 deletion in LWD and ISS, which results in the loss of a previously uncharacterised SHOX enhancer. The loss of this enhancer may decrease SHOX transcription, resulting in LWD or ISS due to SHOX haploinsufficiency.

Description of the genetic variants identified in a cohort of patients diagnosed with localized anal squamous cell carcinoma and treated with panitumumab.

Squamous cell carcinoma is the most frequent histologic type of anal carcinoma. The standard of care since the 1970s has been a combination of 5-fluorouracil, mitomycin C, and radiotherapy. This treatment is very effective in T1/T2 tumors (achieving complete regression in 80-90% of tumors). However, in T3/T4 tumors, the 3-year relapse free survival rate is only 50%. The VITAL trial aimed to assess the efficacy and safety of panitumumab in combination with this standard treatment. In this study, 27 paraffin-embedded samples from the VITAL trial and 18 samples from patients from daily clinical practice were analyzed by whole-exome sequencing and the influence of the presence of genetic variants in the response to panitumumab was studied. Having a moderate- or high-impact genetic variant in PIK3CA seemed to be related to the response to panitumumab. Furthermore, copy number variants in FGFR3, GRB2 and JAK1 were also related to the response to panitumumab. These genetic alterations have also been studied in the cohort of patients from daily clinical practice (not treated with panitumumab) and they did not have a predictive value. Therefore, in this study, a collection of genetic alterations related to the response with panitumumab was described. These results could be useful for patient stratification in new anti-EGFR clinical trials.

High prevalence of variants in skeletal dysplasia associated genes in individuals with short stature and minor skeletal anomalies.

OBJECTIVE: Next generation sequencing (NGS) has expanded the diagnostic paradigm turning the focus to the growth plate. The aim of the study was to determine the prevalence of variants in genes implicated in skeletal dysplasias in probands with short stature and mild skeletal anomalies. DESIGN: Clinical and radiological data were collected from 108 probands with short stature and mild skeletal anomalies. METHODS: A customized skeletal dysplasia NGS panel was performed. Variants were classified using ACMG recommendations and Sherloc. Anthropometric measurements and skeletal anomalies were subsequently compared in those with or without an identified genetic defect. RESULTS: Heterozygous variants were identified in 21/108 probands (19.4%). Variants were most frequently identified in ACAN (n = 10) and IHH (n = 7) whilst one variant was detected in COL2A1, CREBBP, EXT1, and PTPN11. Statistically significant differences (P < 0.05) were observed for sitting height/height (SH/H) ratio, SH/H ratio standard deviation score (SDS), and the SH/H ratio SDS >1 in those with an identified variant compared to those without. CONCLUSIONS: A molecular defect was elucidated in a fifth of patients. Thus, the prevalence of mild forms of skeletal dysplasias is relatively high in individuals with short stature and mild skeletal anomalies, with variants in ACAN and IHH accounting for 81% of the cases. An elevated SH/H ratio appears to be associated with a greater probability in detecting a variant, but no other clinical or radiological feature has been found determinant to finding a genetic cause. Currently, we cannot perform extensive molecular studies in all short stature individuals so detailed clinical and radiological phenotyping may orientate which are the candidate patients to obtain worthwhile results. In addition, detailed phenotyping of probands and family members will often aid variant classification.

CDKN1C (p57(Kip2)) analysis in Beckwith-Wiedemann syndrome (BWS) patients: Genotype-phenotype correlations, novel mutations, and polymorphisms.

Beckwith-Wiedemann syndrome (BWS) is an overgrowth syndrome characterized by macroglossia, macrosomia, and abdominal wall defects. It is a multigenic disorder caused in most patients by alterations in growth regulatory genes. A small number of individuals with BWS (5-10%) have mutations in CDKN1C, a cyclin-dependent kinase inhibitor of G1 cyclin complexes that functions as a negative regulator of cellular growth and proliferation. Here, we report on eight patients with BWS and CDKN1C mutations and review previous reported cases. We analyzed 72 patients (50 BWS, 17 with isolated hemihyperplasia (IH), three with omphalocele, and two with macroglossia) for CDKN1C defects with the aim to search for new mutations and to define genotype-phenotype correlations. Our findings suggest that BWS patients with CDKN1C mutations have a different pattern of clinical malformations than those with other molecular defects. Polydactyly, genital abnormalities, extra nipple, and cleft palate are more frequently observed in BWS with mutations in CDKN1C. The clinical observation of these malformations may help to decide which genetic characterization should be undertaken (i.e., CDKN1C screening), thus optimizing the laboratory evaluation for BWS.

Comprehensive Characterization of the Mutational Landscape in Localized Anal Squamous Cell Carcinoma.

Anal squamous cell carcinoma (ASCC) is a rare neoplasm. Chemoradiotherapy is the standard of care, with no therapeutic advances achieved over the past three decades. Thus, a deeper molecular characterization of this disease is still necessary. We analyzed 46 paraffin-embedded tumor samples from patients diagnosed with primary ASCC by exome sequencing. A bioinformatics approach focused in the identification of high-impact genetic variants, which may act as drivers of oncogenesis, was performed. The relation between genetics variants and prognosis was also studied. The list of high-impact genetic variants was unique for each patient. However, the pathways in which these genes are involved are well-known hallmarks of cancer, such as angiogenesis or immune pathways. Additionally, we determined that genetic variants in BRCA2, ZNF750, FAM208B, ZNF599, and ZC3H13 genes are related with poor disease-free survival in ASCC. This may help to stratify the patient's prognosis and open new avenues for potential therapeutic intervention. In conclusion, sequencing of ASCC clinical samples appears an encouraging tool for the molecular portrait of this disease.

Genetic screening of a Dutch population with isolated GH deficiency (IGHD).

OBJECTIVE: Five per cent to 30% of cases of idiopathic isolated GH deficiency (IGHD) have first-degree relatives with short stature, which is suggestive of a genetic aetiology. The HYPOPIT study aimed to obtain an overall picture of gene encoding pituitary GH (GH1) and gene encoding GH releasing hormone-receptor (GHRHR) defects in a Dutch IGHD cohort and to relate them with clinical parameters. DESIGN, PATIENTS AND MEASUREMENTS: Genetic analysis was performed of exons and exon-intron boundaries of GH1 and GHRHR in 89 Caucasian IGHD patients from 81 families, using denaturing high-performance liquid chromatography (dHPLC), DNA sequencing and multiplex ligation-dependent probe amplification. In addition, we performed functional studies on novel identified GH1 exonic variants. RESULTS: Five different heterozygous GH1 mutations were present in 5 out of 81 participating families (6.1%), whereas no mutations in GHRHR were found. Patients with IGF-I SDS < -4.0 and peak GH levels < 5.7 mU/l had a mutation frequency of 40%, in contrast to 6.8% in patients with only one criterion, and 0.0% in patients with none of these criteria (P = 0.00007). Five new GH1 and two GHRHR variants were also identified; two of them (GH1 F92L and D153H) caused a marked reduction of GH secretion in vitro. CONCLUSION: GH1 and GHRHR mutations are rare in Caucasian Dutch IGHD patients, which suggests the involvement of other genetic determinants in the aetiology of IGHD. IGF-I < -4.0 and peak GH levels < 5.7 mU/l are strong predictors of GH1 mutations in the studied population.

A novel GLI2 mutation responsible for congenital hypopituitarism and polymalformation syndrome.

OBJECTIVE: We report a novel GLI2 frameshift mutation and describe the phenotypic spectrum of mutations within this gene. PATIENTS AND METHODS: A male with congenital hypopituitarism and polymalformation syndrome was clinically, biochemically and neuroradiologically characterized. Genetic analysis for congenital hypopituitarism was performed using a targeted NGS custom gene panel. RESULTS: A heterozygous frameshift mutation, NM_005270.4:c.2125del, p.(Leu709Trpfs*15), was identified in GLI2 exon 12. This mutation has not been previously reported and confirms the diagnosis of Culler-Jones syndrome (MIM #615849). CONCLUSION: GLI2 mutations should be suspected in the presence of congenital hypopitutarism, characteristic facial abnormalities and polydactyly.

Primary acid-labile subunit deficiency due to recessive IGFALS mutations results in postnatal growth deficit associated with low circulating insulin growth factor (IGF)-I, IGF binding protein-3 levels, and hyperinsulinemia.

CONTEXT: Up to 90% of circulating IGF-I and IGF-II are carried bound to either IGF binding protein (IGFBP)-3 or IGFBP-5 and the acid-labile subunit (ALS) in the form of tertiary complexes that extend their circulating half-life. Three cases of complete ALS deficiency have been recently reported in short-stature patients with very low circulating IGF-I and IGFBP-3 levels who presented with homozygous or compound heterozygous mutations in the ALS encoding gene (IGFALS; 16p13.3), thus supporting a role for ALS in the regulation of the bioavailability of IGFs during postnatal growth. OBJECTIVE: We present the molecular and clinical characterization of two novel IGFALS mutations that caused complete ALS deficiency in three unrelated patients with postnatal growth deficit, low IGF-I and IGFBP-3 levels, and no GH deficiency. RESULTS: IGFALS mutation screening identified a novel homozygous IGFALS missense mutation, which altered a conserved residue, N276S, in two of the probands. The third proband presented a novel homozygous nonsense mutation, Q320X, that is predicted to generate a severely truncated ALS protein. The affected probands presented a similar phenotype characterized by a moderate postnatal growth deficit associated with undetectable ALS, low IGF-I, IGF-II, and IGFBP-3, and hyperinsulinemia, and, in two cases, delayed puberty. CONCLUSIONS: Primary ALS deficiency due to IGFALS mutations should be considered as a possible cause of postnatal growth deficit in IGF-I-deficient patients in the absence of GH deficiency or insensitivity. Determination of serum ALS levels and basal insulinemia can be helpful in the differential diagnosis of patients with idiopathic IGF-I deficiency.

A new variant in PHKA2 is associated with glycogen storage disease type IXa.

Glucogenosis type IX is caused by pathogenic variants of the PHKA2 gene. Herein, we report a patient with clinical symptoms compatible with Glycogen Storage Disease type IXa. PYGL, PHKA1, PHKA2, PHKB and PHKG2 genes were analyzed by Next Generation Sequencing (NGS). We identified the previously undescribed hemizygous missense variant NM_000292.2(PHKA2):c.1963G > A, p.(Glu655Lys) in PHKA2 exon 18. In silico analyses showed two possible pathogenic consequences: it affects a highly conserved amino acid and disrupts the exon 18 canonical splice donor site. The variant was found as a "de novo" event.

[Spanish patients with central hypoventilation syndrome included in the European Registry. The 2015 data]. / Pacientes españoles con síndrome de hipoventilación central incluidos en el Registro europeo. Datos del 2015.

INTRODUCTION: Congenital Central Hypoventilation Syndrome (CCHS) is a very rare genetic disease. In 2012 the European Central Hypoventilation Syndrome (EuCHS) Consortium created an online patient registry in order to improve care. AIM: To determine the characteristics and outcomes of Spanish patients with CCHS, and detect clinical areas for improvement. MATERIALS AND METHOD: An assessment was made on the data from Spanish patients in the European Registry, updated on December 2015. RESULTS: The Registry contained 38 patients, born between 1987 and 2013, in 18 hospitals. Thirteen (34.2%) were older than 18 years. Three patients had died. Genetic analysis identified PHOX2B mutations in 32 (86.5%) out of 37 patients assessed. The 20/25, 20/26 and 20/27 polyalanine repeat mutations (PARMs) represented 84.3% of all mutations. Longer PARMs had more, as well as more severe, autonomic dysfunctions. Eye diseases were present in 47%, with 16% having Hirschsprung disease, 13% with hypoglycaemia, and 5% with tumours. Thirty patients (79%) required ventilation from the neonatal period onwards, and 8 (21%) later on in life (late onset/presentation). Eight children (21%) were using mask ventilation at the first home discharge. Five of them were infants with neonatal onset, two of them, both having a severe mutation, were switched to tracheostomy after cardiorespiratory arrest at home. Approximately one-third (34.3%) of patients were de-cannulated and switched to mask ventilation at a mean age of 13.7 years. Educational reinforcement was required in 29.4% of children attending school. CONCLUSION: The implementation of the EuCHS Registry in Spain has identified some relevant issues for optimising healthcare, such as the importance of genetic study for diagnosis and assessment of severity, the high frequency of eye disease and educational reinforcement, as well as some limitations in ventilatory techniques.

PAR1 deletions downstream of SHOX are the most frequent defect in a Spanish cohort of Léri-Weill dyschondrosteosis (LWD) probands.

Léri-Weill dyschondrosteosis (LWD) is a skeletal dysplasia characterized by disproportionate short stature and Madelung deformity. Mutations or deletions of the SHOX gene have been previously identified as the main cause of LWD. We recently identified the existence of a second class of pseudoautosomal region 1 (PAR1) deletions which do not include SHOX, implicated in the etiopathogenesis of LWD. The deletions map at least 30-250 kb downstream of SHOX, are variable in size and clearly cosegregate with the LWD phenotype. In order to determine the frequency of this new type of deletions in the Spanish population we analyzed the distribution of PAR1 defects, including the screening of SHOX deletions, mutations, and PAR1 deletions downstream of SHOX, in a total of 26 LWD probands by a combination of MLPA, microsatellite analysis, SNP genotyping, dHPLC, and DNA sequencing. A molecular defect was identified in 16/26 LWD patients (61.5%): 10 PAR1 deletions downstream of SHOX, four SHOX encompassing deletions, and two SHOX mutations. No apparent phenotypic differences were observed between patients with SHOX defects and those with PAR1 deletions downstream of SHOX. In the examined cohort of Spanish LWD probands, PAR1 deletions downstream of SHOX represent the highest proportion of identified mutations (38%) compared to SHOX deletions (15%) and mutations (8%). As a consequence of our findings, the screening of this region should be included in the routine genetic testing of LWD. Also, LWD patients who tested negative for SHOX defects should be re-evaluated for PAR1 deletions downstream of SHOX.