Biochemical diagnosis of Sanfilippo disorder types A and B.

BACKGROUND: One of the 11 recognized mucopolysaccharidosis (MPS) diseases is Sanfilippo. It is autosomal recessive in its mode of transmission. There are four subtypes of Sanfilippo (A, B, C, and D). The most worldwide prevalent subtypes of mucopolysaccharidosis type III (MPS III) are A and B followed by C and D subtypes. To estimate the frequency of MPS IIIA among MPS III patients, we diagnose and compare their clinical features with those of MPS IIIB and also compare the prevalence of MPS IIIB versus MPS IIIA among diagnosed cases at the Biochemical Genetic Department at NRC. For every case that was referred, the quantitative determination of urine Glycosaminoglycans (GAGs) was assessed. Two-dimensional electrophoresis (2DE) of GAGs extracted from urine was performed on all cases with high urinary GAG levels. Both N-sulphoglucosamine sulphohydrolase (MPS IIIA) and N-alpha-acetylglucosaminidase (MPS IIIB) enzyme activity were determined fluorometrically. RESULTS: From November 2019 to May 2022, 535 cases were referred to the National Research Centre's Biochemical Genetics Department. 233 (43%) MPS cases were diagnosed with high urinary GAG levels for their ages. 73 (31.3%) MPS III cases were diagnosed by 2DE out of the 233 MPS cases. Plasma N-alpha-acetylglucosaminidase enzyme assay was insufficient in 36 (49.3%) patients (Sanfilippo type B), while N-sulphoglucosamine sulphohydrolase enzyme activity was deficient in 15 (20.6%) patients. The other 22 (30.1%) patients are either Sanfilippo type C or D. CONCLUSION: N-sulphoglucosamine sulphohydrolase enzyme activity was measured for the first time in Egypt. Thirty-one percent of all diagnosed MPS cases during the last 3 years were MPS type III, making Sanfilippo the most common MPS type among the referred cases to our Biochemical Genetics Department. MPS IIIA accounts for 20.6% of MPSIII cases in this study. Still, MPS type IIIB is the commonest type among diagnosed patients.

Congenital leptin and leptin receptor deficiencies in nine new families: identification of six novel variants and review of literature.

Early childhood obesity is a real public health problem worldwide. Identifying the etiologies, especially treatable and preventable causes, can direct health professionals toward proper management. Measurement of serum leptin levels is helpful in the diagnosis of congenital leptin and leptin receptor deficiencies which are considered important rare causes of early childhood obesity. The main aim of this study was to investigate the frequency of LEP, LEPR, and MC4R gene variants among a cohort of Egyptian patients with severe early onset obesity. The current cross-sectional study included 30 children who developed obesity during the first year of life with BMI > 2SD (for age and sex). The studied patients were subjected to full medical history taking, anthropometric measurements, serum leptin and insulin assays, and genetic testing of LEP, LEPR and MC4R. Disease causing variants in LEP and LEPR were identified in 10/30 patients with a detection rate of 30%. Eight different homozygous variants (two pathogenic, three likely pathogenic, and three variants of uncertain significant) were identified in the two genes, including six previously unreported LEPR variants. Of them, a new frameshift variant in LEPR gene (c.1045delT, p.S349Lfs*22) was recurrent in two unrelated families and seems to have a founder effect in our population. In conclusion, we reported ten new patients with leptin and leptin receptor deficiencies and identified six novel LEPR variants expanding the mutational spectrum of this rare disorder. Furthermore, the diagnosis of these patients helped us in genetic counseling and patients' managements specially with the availability of drugs for LEP and LEPR deficiencies.

Advances in genomic diagnosis of a large cohort of Egyptian patients with disorders of sex development.

Disorders/differences of sex development (DSD) comprise a group of congenital disorders that affect the genitourinary tract and usually involve the endocrine and reproductive system. The aim of this work was to identify genetic variants responsible for disorders of human urogenital development in a cohort of Egyptian patients. This three-year study included 225 patients with various DSD forms, referred to the genetic DSD and endocrinology clinic, National Research Centre, Egypt. The patients underwent thorough clinical examination, hormonal and imaging studies, detailed cytogenetic and fluorescence in situ hybridization analysis, and molecular sequencing of genes known to commonly cause DSD including AR, SRD5A2, 17BHSD3, NR5A1, SRY, and WT1. Whole exome sequencing (WES) was carried out for 18 selected patients. The study revealed a high rate of sex chromosomal DSD (33%) with a wide array of cytogenetic abnormalities. Sanger sequencing identified pathogenic variants in 33.7% of 46,XY patients, while the detection rate of WES reached 66.7%. Our patients showed a different mutational profile compared with that reported in other populations with a predominance of heritable DSD causes. WES identified rare and novel pathogenic variants in NR5A1, WT1, HHAT, CYP19A1, AMH, AMHR2, and FANCA and in the X-linked genes ARX and KDM6A. In addition, digenic inheritance was observed in two of our patients and was suggested to be a cause of the phenotypic variability observed in DSD.

Novel AMH and AMHR2 Mutations in Two Egyptian Families with Persistent Müllerian Duct Syndrome.

Anti-müllerian hormone (AMH) is produced by Sertoli cells and signals through 2 transmembrane receptors (AMHR), specific types I and II, leading to regression of müllerian ducts during fetal male sex differentiation. Mutations in AMH and AMHR2 lead to the persistence of müllerian ducts in males which is transmitted in a recessive pattern. Here, we report 2 Egyptian DSD (disorder of sex development) patients reared as males who presented with bilateral cryptorchidism and otherwise normal male external genitalia and who both had a 46,XY karyotype. The first patient presented at the age of 2 years. Laparoscopic surgery revealed a uterus and fallopian tubes with the presence of 2 gonads, and biopsy and pathology revealed prepubertal testicular tissue showing small-sized tubules with mostly Sertoli cells and very few spermatogonia, edematous stroma, and no detectable ovarian tissue. The second patient presented at the age of 3 years. Laparoscopic surgery revealed a uterus and fallopian tubes, and serum AMH was very low (0.1 ng/mL). Molecular studies revealed a novel missense mutation in the AMHR2 gene in the first patient (c.767A>C; p.H256P) and a novel frameshift mutation in the AMH gene in the second patient (c.203delC; p.L70Cfs*7). We conclude that persistent müllerian ducts should be included in the differential diagnosis of cryptorchidism.

Identification of NR5A1 Mutations and Possible Digenic Inheritance in 46,XY Gonadal Dysgenesis.

The phenotypic spectrum of patients carrying NR5A1 mutations ranges from 46,XY gonadal dysgenesis to male infertility. Phenotypic variability could be due to digenic or oligogenic inheritance of pathogenic variants in other testis-determining genes. Here, exome sequencing identified 2 pathogenic de novo NR5A1 mutations in 2 patients with 46,XY gonadal dysgenesis, p.Q206Tfs*20 and p.Arg313Cys. The latter patient also carried a missense mutation in MAP3K1. Our data extend the number of NR5A1 gene mutations associated with gonadal dysgenesis. The combination of an NR5A1 mutation with a MAP3K1 variant may explain the phenotypic variability associated with NR5A1 mutations.

Clinical and Radiographic Evaluation of Immediate Loaded Dental Implants With Local Application of Melatonin: A Preliminary Randomized Controlled Clinical Trial.

Immediate loading of dental implants in situations where low bone density exist, such as the posterior maxillary region, became possible recently after the introduction of biomimetic agents. This 1-year preliminary clinical trial was carried out to clinically and radiographically evaluate immediate-loaded 1-piece implants with local application of melatonin in the osteotomy site as a biomimetic material. 14 patients with missing maxillary premolars were randomized to receive 14 implants of 1-piece type that were subjected to immediate loading after 2 weeks of initial placement. Group I included 7 implants with acid-etched surface while group II included 7 implants with acid-etched surface combined with local application of melatonin gel at the osteotomy site. Patients were recalled for follow up at 1, 3, 6, and 12 months after loading. All implants were considered successful after 12 months of follow-up. Significant difference (P < 0.05) was found between both groups at 1 month of implant loading when considering the implant stability. At 1 and 3 months there were significant differences in the marginal bone level between the 2 groups. These results suggest that the local application of melatonin at the osteotomy site is associated with good stability and minimal bone resorption. However, more studies for longer follow-up periods are required to confirm the effect of melatonin hormone on osseointegration of dental implants.

Severe Early-Onset Obesity Due to Bioinactive Leptin Caused by a p.N103K Mutation in the Leptin Gene.

CONTEXT: Congenital leptin deficiency is a very rare cause of severe early-onset obesity. We recently characterized a mutation in the leptin gene (p.D100Y), which was associated with detectable leptin levels and bioinactivity of the hormone. CASE DESCRIPTION: We now describe two siblings, a 9-year-old girl and a 6-year-old boy with severe early-onset obesity and hyperphagia, both homozygous for a c.309C>A substitution in the leptin gene leading to a p.N103K amino acid exchange in the protein and detectable circulating levels of leptin. In vitro experiments in a heterologous cell system demonstrated that the mutated protein was biologically inactive. Treatment with sc recombinant human leptin led to rapid improvement of eating behavior and weight loss. CONCLUSIONS: Sequencing of the leptin gene may need to be considered in hyperphagic, severely obese children with detectable levels of circulating leptin.

Indicators of the metabolic syndrome in obese adolescents.

INTRODUCTION: To assess the prevalence of metabolic risk indicators for the metabolic syndrome (MS) in a sample of obese Egyptian adolescents and to compare anthropometric and biochemical parameters in subjects with one or two parameters of the MS with those who meet MS criteria. MATERIAL AND METHODS: A descriptive, cross-sectional study was conducted on 300 obese adolescents, with a mean age of 15.45 ±2.54 years. Variables examined included body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR), systolic and diastolic blood pressure (BP), fasting blood glucose, cholesterol, triglycerides (TG), high-density lipoprotein (HDL), low-density lipoproteins (LDL), insulin and insulin resistance (IR) measured by Homeostasis Model Assessment-Insulin Resistance (HOMA-IR). Receiver operating characteristic (ROC) curve analysis was used to determine the predictive powers of anthropometric parameters associated with increased risk for the MS. RESULTS: The overall prevalence of the MS was 20%. Individuals meeting 3 or more MS criteria had significantly higher levels of BP, TG, glucose, insulin and HOMA-R and low HDL levels compared with those who had 1 or 2 MS criteria. Area under the curve (AUC) for identifying the MS risk factors was the highest for WHR, followed by WC and BMI in both genders (p < 0.001). CONCLUSIONS: The most prevalent metabolic risk factors that compose the MS were arterial hypertension, low HDL and hypertriglyceridemia; BMI tended to be the weakest index for identifying MS risk factors, while WHR was the best predictive index in both genders.

LASER sintered one-piece early-loaded dental implants for mandibular premolars replacement.

This study was designed to evaluate laser-sintered early-loaded 1-piece implants (OPI) based on clinical and radiographic findings. Thirty OPI were placed in the mandibular premolar area and subjected to early loading after 3 weeks of initial placement; patients were followed up for 6 months. Clinical evaluation included pocket depth, gingival health, implant stability, and esthetics. Periapical radiographs were used to measure the marginal bone loss (MBL). All implants were considered successful resulting in a survival rate of 100%. A remarkable difference (P < 0.01) existed when comparing MBL levels at 1 month with those at 3 and 6 months. Significant differences (P < 0.01) existed when comparing implant stability at 1 month to 3 months and at 3 months to 6 months. Moreover, significant differences (P < 0.01) were observed when comparing peri-implant probing depth at 1 month to that at 3 and 6 months on both the mesial and distal sides. The mean value of pink esthetic score was 11 at time of final restoration. The laser-treated early-loaded OPI design is associated with satisfactory clinical and radiographic follow-up results and it is a good alternative to the 2-piece design.

Early-loaded laser-sintered versus acid-etched one-piece dental implants for mandibular premolars replacement: a preliminary study.

AIM: Early loading of dental implants can simplify treatment and increase patient's satisfaction. This 1-year preliminary clinical trial aimed to clinically and radiographically evaluate early-loaded one-piece implants that had either laser-sintered or acid-etched surfaces. MATERIALS AND METHODS: Sixty patients with missing mandibular premolars received 60 implants of one-piece type that were subjected to early loading after 3 weeks of initial placement. Group 1 included 30 implants with laser-sintered surface while group 2 included 30 implants with acid-etched surface. Patients were recalled for follow-up at 1, 3, 6, and 12 months after loading. RESULTS: No significant difference (P > 0.05) was found between the 2 implant groups at 1, 3, 6, and 12 months of implant loading, and all implants were considered successful after 12 months of follow-up. CONCLUSIONS: These preliminary results suggest that these implants are associated with satisfactory clinical and radiographic outcomes. Laser versus acid-etched surface treatments did not show any significant difference among different clinical measures or radiographic evaluations at different follow-up times. However, wider application for longer follow-up periods is required for further conclusive recommendations.

A novel mutation (c.2735_2736delTC) in the androgen receptor gene in 46,XY females with complete androgen insensitivity syndrome in an Egyptian family.

BACKGROUND: Androgen insensitivity syndrome (AIS) results from resistance of the target tissues to the effect of the androgenic hormones producing a phenotype with varying degrees of feminization ranging from male infertility to completely normal female external genitalia. Androgen receptor (AR) is a transcription factor that interacts with the androgenic steroids that act as ligands activating the AR, and via different cellular mechanisms, the activated AR binds to the DNA of target tissues to induce the desired biological changes. To date, more than 800 different mutations in the AR gene have been identified in patients with AIS and the majority of these mutations are localized in the ligand-binding domain. METHODS: Here we describe an Egyptian family with 7 affected 46,XY females with complete androgen insensitivity. RESULTS: Mutational analysis of the AR gene revealed a novel frameshift mutation in exon 8 of the gene c.2735_2736delTC. CONCLUSION: This study extends the number of AR gene mutations identified so far. Further, it confirms that AR gene mutations are the most frequent cause of 46,XY disorder of sexual development, with higher frequency in the complete phenotype.

Association of serum paraoxonase enzyme activity and oxidative stress markers with dyslipidemia in obese adolescents.

OBJECTIVES: The aim of the present study was to investigate the serum paraoxonase 1 (PON1) concentration and oxidative stress markers and assess its relations with the biochemical parameters in obese adolescents. MATERIALS AND METHODS: One hundred and fifty obese adolescents (range 16-18 years) and 150 healthy age- and sex-matched controls were enrolled in the study. The data were extracted from a project entitled "Obesity among Youth: Lifestyle and Genetic Factors" funded by the Science and Technology Development Fund, Egypt. Serum paraoxonase 1 (PON1), nitric oxide (NO), and malonaldehyde were measured. Anthropometry, fasting glucose, insulin concentrations, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, triglycerides, systolic and diastolic blood pressure (BP) were measured. Insulin resistance was determined by Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). Diagnostic accuracy of oxidative markers to identify dyslipidemia was calculated with ROC analysis. RESULTS: The study showed that PON1 activity was significantly lower in obese adolescents than controls. Obese adolescents had significant lower NO level and significant increased MA values as compared to controls. PON1 was negatively correlated with MAD and body mass index in obese subjects. Obese adolescents showed dyslipidemia and increased blood pressure and HOMA-IR values. PON1 had high area under the curve in ROC analysis for identifying dyslipidemia in obese subjects. CONCLUSIONS: Our results indicate that obese subjects have increased oxidative stress and decreased PON1 activity. The lower paraoxonase level might contribute to the greater risk of dyslipidemia, insulin resistance, high blood pressure that are considered as important components in the pathogenesis of the metabolic syndrome in obese adolescents.

Hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia in four Egyptian families: report of three novel mutations in the vitamin D receptor gene.

OBJECTIVE: To study the vitamin D receptor (VDR) gene in five Egyptian patients with severe rickets and the clinical features of hereditary vitamin D-resistant rickets, including hypocalcemia, hypophosphatemia, total alopecia, and elevated serum levels of 1,25-dihydroxyvitamin D. STUDY DESIGN: We amplified and sequenced DNA samples from blood from the patients, their parents, and available family members. RESULTS: DNA sequence analyses of the VDR gene showed three novel mutations (p.Y295X, p.R343C, and p.R391H) and a previously reported one (p.R30X) in four patients, whereas no mutation was found in one patient. Mutations cosegregated perfectly with affected individuals in all families, and did not exist in unaffected family members or 200 ethnically matched chromosomes. CONCLUSION: Three novel deleterious mutations in the VDR ligand-binding domain were identified, which are expected to render the VDR nonfunctional. Successful treatment with frequent high doses of oral calcium and calcidol was evident in all patients; however, hair growth occurred only in one patient.

Analysis of the gene coding for steroidogenic factor 1 (SF1, NR5A1) in a cohort of 50 Egyptian patients with 46,XY disorders of sex development.

OBJECTIVE: Steroidogenic factor 1 (SF1, NR5A1) is a key transcriptional regulator of genes involved in the hypothalamic-pituitary-gonadal axis. Recently, SF1 mutations were found to be a frequent cause of 46,XY disorders of sex development (DSD) in humans. We investigate the frequency of NR5A1 mutations in an Egyptian cohort of XY DSD. DESIGN: Clinical assessment, endocrine evaluation and genetic analysis of 50 Egyptian XY DSD patients (without adrenal insufficiency) with a wide phenotypic spectrum. METHODS: Molecular analysis of NR5A1 gene by direct sequencing followed by in vitro functional analysis of the two novel missense mutations detected. RESULTS: Three novel heterozygous mutations of the coding region in patients with hypospadias were detected. p.Glu121AlafsX25 results in severely truncated protein, p.Arg62Cys lies in DNA-binding zinc finger, whereas p.Ala154Thr lies in the hinge region of SF1 protein. Transactivation assays using reporter constructs carrying promoters of anti-Müllerian hormone (AMH), CYP11A1 and TESCO core enhancer of Sox9 showed that p.Ala154Thr and p.Arg62Cys mutations result in aberrant biological activity of NR5A1. A total of 17 patients (34%) harboured the p.Gly146Ala polymorphism. CONCLUSION: We identified two novel NR5A1 mutations showing impaired function in 23 Egyptian XY DSD patients with hypospadias (8.5%). This is the first study searching for NR5A1 mutations in oriental patients from the Middle East and Arab region with XY DSD and no adrenal insufficiency, revealing a frequency similar to that in European patients (6.5-15%). We recommend screening of NR5A1 in patients with hypospadias and gonadal dysgenesis. Yearly follow-ups of gonadal function and early cryoconservation of sperms should be performed in XY DSD patients with NR5A1 mutations given the risk of future fertility problems due to early gonadal failure.

A novel mutation in the leptin gene (W121X) in an Egyptian family.

Congenital leptin deficiency is a rare recessively inherited condition due to homozygous mutations in the LEP gene. To date, only nine mutations have been identified in the LEP gene (p.L72S, p.N103K, p.R105W, p.H118L, p.S141C, c.104_106delTCA, c.135del3bp, c.398delG and c.481_482delCT). In this study we present a novel homozygous nonsense mutation (W121X) in LEP in a twelve year old obese male and his severely obese sister. As this disorder is treatable with recombinant leptin, it is intriguing to report a novel homozygous nonsense mutation in LEP in two obese children of consanguineous parents. These patients showed features in accordance with leptin deficiency.

Long interspersed nuclear element-1 (LINE1)-mediated deletion of EVC, EVC2, C4orf6, and STK32B in Ellis-van Creveld syndrome with borderline intelligence.

Previous work has shown Ellis-van Creveld (EvC) patients with mutations either in both alleles of EVC or in both alleles of EVC2. We now report affected individuals with the two genes inactivated on each allele. In a consanguineous pedigree diagnosed with EvC and borderline intelligence, we detected a 520-kb homozygous deletion comprising EVC, EVC2, C4orf6, and STK32B, caused by recombination between long interspersed nuclear element-1 (LINE-1 or L1) elements. Patients homozygous for the deletion are deficient in EVC and EVC2 and have no increase in the severity of the EvC typical features. Similarly deletion carriers demonstrate absence of digenic inheritance in EvC. Further, the phenotype of these patients suggests that the EVC-STK32B deletion also leads to mild mental retardation and reveals that loss of the novel genes C4orf6 and STK32B causes at most mild mental deficit. In an EvC compound heterozygote of different ethnic origin we identified the same LINE-to-LINE rearrangement due to a different recombination event. These findings highlight the importance of L1 repetitive sequences in human genome architecture and disease.

Assessment of pubertal development in Egyptian girls.

Puberty is a significant event of human growth and maturation associated with marked physiological and psychological changes. The aim of this study was to assess normal pubertal development in Egyptian girls to define normal, precocious and delayed puberty. The present study included a cross-sectional sample of 1,550 normal Egyptian girls of high and middle socioeconomic class living in Cairo. Their ages ranged from 6.5 to 18.5 years. Pubertal assessment was made according to Tanner staging. The mean menarcheal age (MMA) was estimated using probit analysis. Weight and height were measured and body mass index (BMI) was calculated. The mean age at breast bud stage (B2) was 10.71+/-1.6, pubic hair stage (PH2) was 10.46+/-1.36, while axillary hair stage (A2) was 11.65+/-1.62 and MMA was 12.44 years. The mean age at attainment of puberty was compared with those of other Egyptian studies and other populations. Girls of the present study started pubertal development and achieved menarche earlier than those of previous Egyptian studies confirming a secular trend. Differences between the present study and other worldwide studies can be attributed to various genetic, racial, geographical, nutritional, and secular trend factors.