Identification of Two Novel Mutations in PKHD1 Gene from Two Families with Polycystic Kidney Disease by Whole Exome Sequencing

Background

Polycystic kidney disease (PKD) is an autosomal recessive disorder resulting from mutations in the PKHD1 gene on chromosome 6 (6p12), a large gene spanning 470 kb of genomic DNA.

Objective

The aim of the present study was to report newly identified mutations in the PKHD1 gene in two Iranian families with PKD.

Materials and Methods

Genetic alterations of a 3-month-old boy and a 27-year-old girl with PKD were evaluated using whole-exome sequencing. The PCR direct sequencing was performed to analyse the co-segregation of the variants with the disease in the family. Finally, the molecular function of the identified novel mutations was evaluated by in silico study.

Results

In the 3 month-old boy, a novel homozygous frameshift mutation was detected in the PKHD1 gene, which can cause PKD. Moreover, we identified three novel heterozygous missense mutations in ATIC, VPS13B, and TP53RK genes. In the 27-year-old woman, with two recurrent abortions history and two infant mortalities at early weeks due to metabolic and/or renal disease, we detected a novel missense mutation on PKHD1 gene and a novel mutation in ETFDH gene.

Conclusion

In general, we have identified two novel mutations in the PKHD1 gene. These molecular findings can help accurately correlate genotype and phenotype in families with such disease in order to reduce patient births through preoperative genetic diagnosis or better management of disorders.

Association of a novel homozygous mutation in the HMGCS2 gene with an HMGCSD in an Iranian patient

BACKGROUND

3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase 2 gene (HMGCS2) encodes a mitochondrial enzyme catalyzing the first reaction of ketogenesis metabolic pathway which provides lipid-derived energy for various organs during times of carbohydrate deprivation, such as fasting. Mutations in this gene are responsible for HMG-CoA synthase deficiency (HMGCSD). The aim of present study was to investigate the association of mutation in the HMGCS2 gene with HMGCSD in a patient with atypical symptoms.

METHODS

The clinical and genetic features of an 8-months-old girl with HMGCSD were evaluated. Molecular genetic testing was conducted using whole-exome sequencing (WES) in order to identify potential disease-causing mutation. The WES finding was confirmed by the polymerase chain reaction (PCR) amplification of the target sequence carried out for the patient and her parents. The PCR products were subjected to direct sequencing using forward and reverse specific primers corresponding to the HMGCS2 gene.

RESULTS

A novel homozygous missense mutation (c.266G>A p.Gly89Asp) was detected in the HMGCS2 gene. Sanger sequencing along with co-segregation analysis of all family members confirmed this novel pathogenic germline mutation. The mutant gene was found to be pathogenic by bioinformatics analysis.

CONCLUSION

To our best knowledge, this is the first report of HMGCSD in Iran which would expand our knowledge about the mutational spectrum of the HMGCS2 gene and the phenotype variations of the disease.

Unexplained facial scar: child abuse or ehlers-danlos syndrome?

Context:

Child abuse is a serious problem, and its physical manifestations can be mimicked by certain diseases and conditions. These conditions can include genetic, congenital and other disorders that may result in poor weight gain, bone fractures or skin lesions that look like bruises or burns.

Case Report:

This paper reports the case of a seven-year-old girl with Ehlers-Danlos Syndrome (EDS), which was misdiagnosed as child abuse. This child was referred to us for treatment of an unexplained facial scar that was alleged to be the result of child abuse.

Conclusion:

When unusual skin presentations are observed, dermatologists should consider the possibility of child abuse to protect the child. Furthermore, they should be aware of the cutaneous abnormalities that mimic injuries associated with abuse to avoid the unnecessary reporting of child abuse.

Effect of zinc supplementation on markers of insulin resistance, oxidative stress, and inflammation among prepubescent children with metabolic syndrome

OBJECTIVE

This trial aimed to evaluate the effects of zinc sulfate in comparison with placebo on markers of insulin resistance, oxidative stress, and inflammation in a sample of obese prepubescent children.

METHODS

This triple-masked, randomized, placebo-controlled, crossover trial was conducted among 60 obese Iranian children in 2008. Participants were randomly assigned to two groups of equal number; one group received 20  mg of elemental zinc and the other group received placebo on a regular daily basis for 8 weeks. After a 4-week washout period, the groups were crossed over. In addition to anthropometric measures and blood pressure, fasting plasma glucose, lipid profile, insulin, apolipoproteins A-1 (ApoA-I) and B, high-sensitivity C-reactive protein (hs-CRP), leptin, oxidized low-density lipoprotein (ox-LDL), and malondialdehyde were determined at all four stages of the study.

RESULTS

Irrespective of the order of receiving zinc and placebo, in both groups, significant decrease was documented for Apo B/ApoA-I ratio, ox-LDL, leptin and malondialdehyde, total and LDL-cholesterol after receiving zinc without significant change after receiving placebo. In groups, hs-CRP and markers of insulin resistance decreased significantly after receiving zinc, but increased after receiving placebo. In both groups, the mean body mass index (BMI) Z-score remained high, after receiving zinc, the mean weight, BMI, BMI Z-score decreased significantly, whereas these values increased after receiving placebo.

CONCLUSION

These results are particularly important in light of the deleterious consequences of childhood obesity and early changes in markers of inflammatory and oxidative stress. We suggest exploring the direct clinical application of zinc supplementation in childhood obesity in future studies.

Effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese children

OBJECTIVE

Zinc, an essential trace element and a component of many enzymes, is involved in the synthesis, storage and release of insulin. The aim of the present study was to assess the effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese children.

DESIGN

This triple-masked, randomized, placebo-controlled cross-over trial was conducted among 60 obese Iranian children in 2008. Pertinent clinical findings, fasting serum glucose, insulin and lipid profile were assessed. Participants were randomly assigned to two groups of equal number; one group received 20mg elemental zinc and the other group received placebo on a regular daily basis for eight weeks. After a 4-week wash-out period, the groups were crossed over.

RESULTS

The mean age of participants was 9.1 +/- 1.1 years. After receiving zinc, the mean fasting plasma glucose (FPG), insulin and HOMA-IR decreased significantly, while body mass index (BMI), waist circumference (WC), LDL-C and triglycerides (TG) did not significantly change. After receiving placebo, the mean FPG, insulin and HOMA-IR increased significantly, while BMI, WC, LDL-C and TG showed a non-significant increase.

CONCLUSION

Besides lifestyle modification, zinc supplementation might be considered as a useful and safe additional intervention treatment for improvement of cardiometabolic risk factors related to childhood obesity.