We report the results of a study carried out to delineate genetic and epidemiological aspects of homocystinuria in the Qatari population. Sixty-four patients with homocystinuria (37 males, 27 females, age 1 to 29 years) from 31 nuclear families were ascertained over a period of more than four years. The incidence of homocystinuria in Qatar was calculated to be > or =1:3000, the highest in the world known so far. All patients in whom data were available were vitamin B6-nonresponsive. Molecular studies were performed in all patients. All 53 patients from tribe M and all three patients from tribe K were homozygous for the mutation c.1006C>T (p.R336C) in the CBS gene, with an additional seven patients resulting from mixed marriages between tribe M and tribe K. A single patient from tribe S was homozygous for mutation c.700G>A (p.D234N) in the CBS gene. Both mutations have been previously reported but involve hypermutable CpG dinculeotides and may be recurrent mutations in the Qatari population. The results of this study illustrate a strong founder effect causing a high prevalence of an autosomal recessive disease in a highly consanguineous Arabian population. Molecular neonatal screening may be suitable for early detection of homocystinuria in this population.

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Renewable energy has become an auspicious alternative to fossil fuel resources due to its sustainability and renewability. In this respect, Photovoltaics (PV) technology is one of the essential technologies. Today, more than 90 % of the global PV market relies on crystalline silicon (c-Si)-based solar cells. This article reviews the dynamic field of Si-based solar cells from high-cost crystalline to low-cost cells and investigates how to preserve high possible efficiencies while decreasing the cost. First, we discuss the various types of c-Si solar cells with different device architectures and report recent developments. Next, thin-film solar cells with their recent advancements are given. Then, Si nanowires solar cells and their recent results are discussed. Finally, we present the most encouraging tendencies in achieving low-cost solar cells utilizing cheap materials like heavily doped silicon wafers.

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