Abstract: Introduction: The isolated haploinsufficiency of the SHOX gene is one of the most common cause of short stature determined by monogenic mutations. The heterozygous deviation of the gene can be detected in 2–15% of patients with idiopathic short stature (ISS), in 50–90% of patients with Leri-Weill dyschondrosteosis syndrome (LWS), and in almost 100% of patients with Turner syndrome. Aim: The aim of our study was to evaluate the frequency of SHOX gene haploinsufficiency in children with ISS, LWS and in patients having Turner syndrome phenotype (TF), but normal karyotype, and to identify the dysmorphic signs characteristic for SHOX gene deficiency. Method: A total of 144 patients were included in the study. Multiplex Ligation-dependent Probe Amplification (MLPA) method was used to identify the SHOX gene haploinsufficiency. The relationships between clinical data (axiological parameters, skeletal disorders, dysmorphic signs) and genotype were analyzed by statistical methods. Results: 11 (7.6%) of the 144 patients showed SHOX gene deficiency with female dominance (8/11, 81% female). The SHOX positive patients had a significantly higher BMI (in 5/11 vs. 20/133 cases, p<0.02) and presented more frequent dysmorphic signs (9/11vs 62/133, p = 0.02). Madelung deformity of the upper limbs was also significantly more frequent among the SHOX positive patients (4/11, i.e. 36%, vs. 14/133, i.e. 10%, p = 0.0066). There were no statistically significant differences between the mean age, mean height and auxological measurements (sitting height/height, arm span/height) between the two groups of patients. Conclusions: The occurrence of SHOX gene haploinsufficiency observed in our population corresponds to the literature data. In SHOX positive patients, in addition to short stature, the dysmorphic signs have a positive predictive value for SHOX gene alterations. However, the SHOX deletion detected in a patient with idiopathic short stature without dysmorphic signs suggest that SHOX deletion analysis can be recommended in patients with ISS. Orv Hetil. 2017; 158(34): 1351–1356.

INTRODUCTION The isolated haploinsufficiency of the SHOX gene is one of the most common cause of short stature determined by monogenic mutations. The heterozygous deviation of the gene can be detected in 2-15% of patients with idiopathic short stature (ISS), in 50-90% of patients with Leri-Weill dyschondrosteosis syndrome (LWS), and in almost 100% of patients with Turner syndrome. AIM The aim of our study was to evaluate the frequency of SHOX gene haploinsufficiency in children with ISS, LWS and in patients having Turner syndrome phenotype (TF), but normal karyotype, and to identify the dysmorphic signs characteristic for SHOX gene deficiency. METHOD A total of 144 patients were included in the study. Multiplex Ligation-dependent Probe Amplification (MLPA) method was used to identify the SHOX gene haploinsufficiency. The relationships between clinical data (axiological parameters, skeletal disorders, dysmorphic signs) and genotype were analyzed by statistical methods. RESULTS 11 (7.6%) of the 144 patients showed SHOX gene deficiency with female dominance (8/11, 81% female). The SHOX positive patients had a significantly higher BMI (in 5/11 vs. 20/133 cases, p<0.02) and presented more frequent dysmorphic signs (9/11vs 62/133, p = 0.02). Madelung deformity of the upper limbs was also significantly more frequent among the SHOX positive patients (4/11, i.e. 36%, vs. 14/133, i.e. 10%, p = 0.0066). There were no statistically significant differences between the mean age, mean height and auxological measurements (sitting height/height, arm span/height) between the two groups of patients. CONCLUSIONS The occurrence of SHOX gene haploinsufficiency observed in our population corresponds to the literature data. In SHOX positive patients, in addition to short stature, the dysmorphic signs have a positive predictive value for SHOX gene alterations. However, the SHOX deletion detected in a patient with idiopathic short stature without dysmorphic signs suggest that SHOX deletion analysis can be recommended in patients with ISS. Orv Hetil. 2017; 158(34): 1351-1356.

The CYP17 gene, located on chromosome 10q24-q25, encodes the cytochrome P450c17 enzyme. Mutations of this gene cause the 17α-hydroxylase/17,20-lyase deficiency, which is a rare, autosomal recessive form of congenital adrenal hyperplasia. Approximately 50 different mutations of the CYP17 gene have been described, of which some mutations have been identified in certain ethnic groups. In this study, we present the clinical history, hormonal findings and mutational analysis of two patients from unrelated families, who were evaluated for hypertension, hypokalemia and sexual infantilism. In the first patient, who was a 37-year-old female, additional studies showed a large myelolipoma in the left adrenal gland, and a smaller tumor in the right adrenal gland. In the second patient, who was a 31-year-old phenotypic female, clinical work-up revealed a 46,XY kariotype, absence of ovaries and presence of testes located in the inner opening of both inguinal canals. Analysis of the CYP17 gene by polymerase chain reaction amplification and direct sequencing demonstrated a novel homozygous mutation of codon 440 from CGC (Arg) to TGC (Cys) in both patients. The effect of this novel mutation on 17α-hydroxylase/17,20-lyase activity was assessed by in vitro studies on the mutant and wild-type P450c17 generated by site-directed mutagenesis and transfected in nonsteroidogenic COS-1 cells. These studies showed that the mutant P450c17 protein was produced in transfected COS-1 cells, but it had negligible 17α-hydroxylase and 17,20-lyase activities. In addition, three-dimensional computerized modeling of the heme-binding site of the P450c17 enzyme indicated that replacement of Arg by Cys at amino acid position 440 predicts a loss of the catalytic activity of the enzyme, as the mutant enzyme containing Cys440 fails to form a hydrogen bond with the propionate group of heme, which renders the mutant enzyme unable to stabilize the proper position of heme. Based on these findings we conclude that expressing the CYP17 gene with functional analysis, combined with three-dimensional computerized modeling of the heme-binding site of the protein provide feasible tools for molecular characterizing of functional consequences of the novel CYP17 mutation on enzyme function.