Individuals born of consanguineous union have segments of their genomes that are homozygous as a result of inheriting identical ancestral genomic segments through both parents. One consequence of this is an increased incidence of recessive disease within these sibships. Theoretical calculations predict that 6% (1/16) of the genome of a child of first cousins will be homozygous and that the average homozygous segment will be 20 cM in size. We assessed whether these predictions held true in populations that have preferred consanguineous marriage for many generations. We found that in individuals with a recessive disease whose parents were first cousins, on average, 11% of their genomes were homozygous (n = 38; range 5%-20%), with each individual bearing 20 homozygous segments exceeding 3 cM (n = 38; range of number of homozygous segments 7-32), and that the size of the homozygous segment associated with recessive disease was 26 cM (n = 100; range 5-70 cM). These data imply that prolonged parental inbreeding has led to a background level of homozygosity increased approximately 5% over and above that predicted by simple models of consanguinity. This has important clinical and research implications.
Background: Autosomal recessive primary microcephaly (MCPH) is a model disease to study human neurogenesis. In affected individuals the brain grows at a reduced rate during fetal life resulting in a small but structurally normal brain and mental retardation. The condition is genetically heterogeneous with mutations in ASPM being most commonly reported. Methods and results: We have examined this further by studying three cohorts of microcephalic children to extend both the phenotype and the mutation spectrum. Firstly, in 99 consecutively ascertained consanguineous families with a strict diagnosis of MCPH, 41 (41%) were homozygous at the MCPH5 locus and all but two families had mutations. Thus, 39% of consanguineous MCPH families had homozygous ASPM mutations. Secondly, in 27 non-consanguineous, predominantly Caucasian families with a strict diagnosis of MCPH, 11 (40%) had ASPM mutations. Thirdly, in 45 families with a less restricted phenotype including microcephaly and mental retardation, but regardless of other neurological features, only 3 (7%) had an ASPM mutation. This report contains 27 novel mutations and almost doubles the number of MCPH associated ASPM mutations known to 57. All but one of the mutations lead to the use of a premature termination codon, 23 were nonsense mutations, 28 deletions or insertions, 5 splicing, and 1 was a translocation. Seventeen of the 57 mutations were recurrent. There were no definitive missense mutations found nor was there any mutation/phenotype correlation. ASPM mutations were found in all ethnic groups studied. Conclusion: This study confirms that mutations in ASPM are the most common cause of MCPH, that ASPM mutations are restricted to individuals with an MCPH phenotype, and that ASPM testing in primary microcephaly is clinically useful.Our most defining feature as a species is our brain with its large size and cognitive functions leading to our great adaptability.
Atorvastatin (AT) is a widely used lipid-regulating drug to reduce cholesterol and triglycerides. Its poor aqueous solubility and hepatic metabolism require development of drug delivery systems able to improve its solubility and bypass hepatic effect. For this purpose, atorvastatin nanostructured lipid carriers (AT-NLCs) were prepared and characterized. AT-NLCs were prepared by emulsification using high-speed homogenization followed by ultrasonication. The prepared NLCs showed particle size between 162.5 ± 12 and 865.55 ± 28 nm while zeta potential values varied between À34 ± 0.29 and À23 ± 0.36 mV. They also showed high encapsulation efficiency (>87%) and amorphous state of the drug in lipid matrix. Pharmacokinetic parameters of optimized formulation (NLC-1; composed of 2% Gelucire V R 43/01, 8% Capryol V R PGMC, 2% Pluronic V R F68 and 0.5% lecithin) revealed 3.6-and 2.1-fold increase in bioavailability as compared to atorvastatin suspension and commercial product (Lipitor V R ), respectively. Administration of NLC-1 led to significant reduction (p < .05) in the rats' serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) and significant increase in highdensity lipoprotein (HDL). This improvement was confirmed histologically by minimizing the associated hepatic steatosis. These investigations demonstrated the superiority of NLCs for improvement of oral bioavailability and in vivo performance of AT.
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