👤 Jessica A Mazen

Parental history of dementia is associated with increased dementia risk. We investigated whether having a parent with dementia is associated with increased peripheral inflammation in middle-aged adults. Participants were from the Offspring Study (n = 1204). Parental dementia status was determined by a diagnostic consensus conference. Plasma chemokine and cytokine concentrations were assayed with Luminex technology. Parental history of dementia was associated with higher levels of eotaxin and lower levels of granulocyte colony-stimulating factor, vascular endothelial growth factor A, and interleukin (IL)-27. IL-18 and epidermal growth factor levels were higher in Black individuals with a parental history of dementia compared to Hispanic individuals with the same history. Women with a parental history of dementia had higher levels of interferon-alpha 2, IL-12p70, soluble CD40 ligand, and IL-18 compared to men with the same history. Parental history of dementia is associated with elevated markers of peripheral inflammation. These associations vary across sex, race, and ethnicity. Show less

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. Show less

Mutations in the HSD17B3 gene are associated with a 46,XY disorder of sexual development (46,XY DSD) as a result of low testosterone production during embryogenesis. To elucidate the molecular basis of the disorder by chemically analyzing four missense mutations in HSD17B3 (T54A, M164T, L194P, G289S) from Egyptian patients with 46,XY DSD. Expression plasmids for wild-type 17β-hydroxysteroid hydrogenase type 3 (17β-HSD3) and mutant enzymes generated by site-directed mutagenesis were transiently transfected into human HEK-293 cells. Protein expression was verified by western blotting and activity was determined by measuring the conversion of radiolabeled Δ Testosterone formation by wild-type and mutant 17β-HSD3 enzymes was compared. Mutations T54A and L194P, despite normal protein expression, completely abolished 17β-HSD3 activity, explaining their severe 46,XY DSD phenotype. Mutant M164T could still produce testosterone, albeit with significantly lower activity compared with wild-type 17β-HSD3, resulting in ambiguous genitalia or a microphallus at birth. The substitution G289S represented a polymorphism exhibiting comparable activity to wild-type 17β-HSD3. Sequencing of the SRD5A2 gene in three siblings bearing the HSD17B3 G289S polymorphism disclosed the homozygous Y91H mutation in the former gene, thus explaining the 46,XY DSD presentations. Molecular modeling analyses supported the biochemical observations and predicted a disruption of cofactor binding by mutations T54A and M164T and of substrate binding by L196P, resulting in the loss of enzyme activity. In contrast, the G289S substitution was predicted to disturb neither the three-dimensional structure nor enzyme activity. Biochemical analysis of mutant 17β-HSD3 enzymes is necessary to understand genotype-phenotype relationships. Biochemical analysis combined with molecular modeling provides insight into disease mechanism. However, the stability of mutant proteins in vivo cannot be predicted by this approach. The 17β-HSD3 G289S substitution, previously reported in other patients with 46,XY DSD, is a polymorphism that does not cause the disorder; thus, further sequence analysis was required and disclosed a mutation in SRD5A2, explaining the cause of 46,XY DSD in these patients. Engeli RT, Tsachaki M, Hassan HA, et al. Biochemical Analysis of Four Missense Mutations in the HSD17B3 Gene Associated With 46,XY Disorders of Sex Development in Egyptian Patients. J Sex Med 2017;14:1165-1174. Show less

17-β-Hydroxysteroid dehydrogenase type 3 deficiency is a rare autosomal recessive cause of 46,XY disorder of sex development. Worldwide, about 30 mutations in the hydroxysteroid (17-beta) dehydrogenase 3 (HSD17B3) gene have been reported, involving all exons except exon 1. Herein, we investigated an Egyptian female with 46,XY karyotype and low testosterone/Δ4-androstenedione ratio. Genomic DNA was extracted from blood samples, and then, direct DNA sequencing of HSD17B3 gene was performed. The patient had a homozygous mutation c.198G>A in exon 1 resulting in a stop codon (p.W50X). The study presents the first mutation to be reported in exon 1 of the HSD17B3 gene. Show less