Fragile X syndrome (FXS), the most common inherited form of developmental delay, is typically caused by CGG-repeat expansion in FMR1. However, little attention has been paid to sequence variants in FMR1. Through the use of pooled-template massively parallel sequencing, we identified 130 novel FMR1 sequence variants in a population of 963 developmentally delayed males without CGG-repeat expansion mutations. Among these, we identified a novel missense change, p.R138Q, which alters a conserved residue in the nuclear localization signal of FMRP. We have also identified three promoter mutations in this population, all of which significantly reduce in vitro levels of FMR1 transcription. Additionally, we identified 10 noncoding variants of possible functional significance in the introns and 3'-untranslated region of FMR1, including two predicted splice site mutations. These findings greatly expand the catalogue of known FMR1 sequence variants and suggest that FMR1 sequence variants may represent an important cause of developmental delay.

Voltage-gated calcium channels play a key role in chemical synaptic transmission by providing the calcium trigger for regulated neurotransmitter release. Genes encoding the primary structural subunit, alpha1, as well as accessory subunits of presynaptic calcium channels have now been identified in a variety of organisms. The cacophony (cac) gene in Drosophila, also known as nightblind A, encodes a voltage-gated calcium-channel alpha1 subunit homologous to vertebrate alpha1 subunits implicated in neurotransmitter release. A recent genetic screen in our laboratory isolated cac(TS2), a conditional cac mutant exhibiting rapid paralysis at elevated temperatures. This mutant has allowed synaptic electrophysiology after acute perturbation of a specific calcium-channel gene product, demonstrating that cac encodes a primary calcium channel functioning in neurotransmitter release. Here we report the molecular lesion in cac(TS2), a missense mutation within a calcium-dependent regulatory domain of the alpha1 subunit, as well as phenotypic rescue of temperature-sensitive and lethal cac mutations by transgenic expression of a wild-type cac cDNA. Notably, rescue of rapid, calcium-triggered neurotransmitter release was achieved by neural expression of a single cDNA containing a subset of alternative exons and lacking any conserved synaptic-protein interaction sequence. Possible implications of these findings are discussed in the context of structure-function studies of synaptic calcium channels, as well as alternative splicing and mRNA editing of the cac transcript.

Female fertility is highly dependent on successful regulation of energy metabolism. Central processes in the hypothalamus monitor the metabolic state of the organism and, together with metabolic hormones, drive the peripheral availability of energy for cellular functions. In the ovary, the oocyte and neighboring somatic cells of the follicle work in unison to achieve successful metabolism of carbohydrates, amino acids, and lipids. Metabolic disturbances such as anorexia nervosa, obesity, and diabetes mellitus have clinically important consequences on human reproduction. In this article, we review the metabolic determinants of female reproduction and their role in infertility.

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Considering the expected cost of achieving one live birth with IVF, PGS is a cost-effective strategy for women older than 37 undergoing IVF. Additional research on patients' willingness-to-pay per live birth would further inform our understanding regarding the cost-effectiveness of PGS.