A very early diagnosis of AlstrÓ§m syndrome by next generation sequencing.

BACKGROUND: Alström syndrome is a rare recessively inherited disorder caused by variants in the ALMS1 gene. It is characterized by multiple organ dysfunction, including cone-rod retinal dystrophy, dilated cardiomyopathy, hearing loss, obesity, insulin resistance, hyperinsulinemia, type 2 diabetes mellitus and systemic fibrosis. Heterogeneity and age-dependent development of clinical manifestations make it difficult to obtain a clear diagnosis, especially in pediatric patients. CASE PRESENTATION: Here we report the case of a girl with Alström syndrome. Genetic examination was proposed at age 22 months when suspected macular degeneration was the only major finding. Next generation sequencing of a panel of genes linked to eye-related pathologies revealed two compound heterozygous variants in the ALMS1 gene. Frameshift variants c.1196_1202del, p.(Thr399Lysfs*11), rs761292021 and c.11310_11313del, (p.Glu3771Trpfs*18), rs747272625 were detected in exons 5 and 16, respectively. Both variants cause frameshifts and generation of a premature stop-codon that probably leads to mRNA nonsense-mediated decay. Validation and segregation of ALMS1 variants were confirmed by Sanger sequencing. CONCLUSIONS: Genetic testing makes it possible, even in childhood, to increase the number of correct diagnoses of patients who have ambiguous phenotypes caused by rare genetic variants. The development of high-throughput sequencing technologies offers an exceptionally valuable screening tool for clear genetic diagnoses and ensures early multidisciplinary management and treatment of the emerging symptoms.

Determination of lead in human placenta tissue employing slurry sampling and detection by electrothermal atomic absorption spectrometry.

A new analytical procedure was developed for the determination of lead in human placental tissue by direct ultrasonic slurry sampling combined with electrothermal atomic absorption spectrometry (SS-ET AAS). Samples of dried and crushed placental tissue were mixed with 10 mL of 0.20% (v/v) HNO3 and homogenised. The slurries were then transferred to autosampler cups where they were sonicated using an ultrasonic probe prior to injection into a graphite tube with an L'vov platform. The effects of several chemical modifiers, including Mg(NO3)2, Pd(NO3)2, and NH4H2PO4, were investigated for the stabilisation of lead during thermal pre-treatment. Lead in the slurries was effectively stabilised up to 1200 °C with the Pd(NO3)2 modifier providing the best results with complete atomisation at 1900 °C. H2O2 was used as a chemical modifier; dilute HNO3 and HCl were examined as slurry media. The limit of detection and the limit of quantification for lead obtained under optimised conditions were 0.17 µg g-1 and 0.56 µg g-1, respectively. The relative standard deviation estimated from twenty replicate measurements of spike solution at a concentration of 50.00 µg L-1 for lead was 1.51%. The accuracy of the method was confirmed by analysis of the standard reference material BCR 185R "Bovine Liver". The proposed technique is simple, sensitive and environmentally friendly, and the risk of contamination is low. The method was applied to lead determination in real samples of human placental tissue. The 14 samples were taken just after delivery at the Gynaecology and Obstetrics Department of the Faculty Hospital with Outpatients Clinic in Bratislava over the course of 2019.

Expanding the phenotype of thrombocytopenia absent radius syndrome with hypospadias.

Rare genetic diseases and syndromes may appear with unique features in some patients. In genetically-solved cases, this situation indicates a phenotypic expansion of the syndrome with additional features (i.e. the disease-associated gene gives rise to unusual clinical presentation). However, this situation can also hide a multilocus pathogenic variation that cannot be solved genetically except by a massive sequencing approach, such as exome sequencing. Here we describe the case of a child with bilateral radial aplasia, transient thrombocytopenia and anemia, cow's milk intolerance, hypospadias, facial dysmorphism, mild hypothyroidism and umbilical and inguinal hernia. Bilaterally absent radius, presence of thumbs and low platelet count are pathognomonic of thrombocytopenia absent radius (TAR) syndrome, but the child also showed other features beyond those reported in the literature. Since various diseases resembling the proband's phenotype required differential diagnosis, clinical exome sequencing was performed. The results showed compound heterozygous mutations in the RBM8A gene, confirming the suspicion of TAR syndrome. A truncating heterozygous variant in the DUOX2 gene, known to be associated with transient thyroid dyshormonogenesis type 6 (TDH6), was also detected and may explain the proband's mild hypothyroidism.

The pathway of lead through the mother's body to the child.

Placenta, the organ on which great attention is concentrated during pregnancy, represents an ineffective barrier to the transfer of hazardous heavy metals, mainly lead, into the foetus. The presence of lead in the placenta is an environmental hazard for a person's future. Due to hormonal changes, lead is released during pregnancy into the bloodstream of the mother from deposits in the bones and in the teeth, where it has accumulated for years as a result of a contaminated environment. Since lead is a neurotoxic metal, exposure to lead during prenatal and postnatal development can cause serious neurocognitive damage and hence the development of an Attention Deficit Hyperactivity Disorder (ADHD) in a developing human. Our work provides an overall picture of the "toxic pathway" of lead through the mother's body, the risks arising from its transplacental transfer and its accumulation in the developing foetus as well as effective prevention to protect all newborns.