Immunohistochemical Study of ASC Expression and Distribution in the Hippocampus of an Aged Murine Model of Alzheimer's Disease.

Neuroinflammation is involved in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD), and is notably dependent on age. One important inflammatory pathway exerted by innate immune cells of the nervous system in response to danger signals is mediated by inflammasomes (IF) and leads to the generation of potent pro-inflammatory cytokines. The protein "apoptosis-associated speck-like protein containing a caspase recruitment domain" (ASC) modulates IF activation but has also other functions which are crucial in AD. We intended to characterize immunohistochemically ASC and pattern recognition receptors (PRR) of IF in the hippocampus (HP) of the transgenic mouse model Tg2576 (APP), in which amyloid-beta (Aß) pathology is directly dependent on age. We show in old-aged APP a significant amount of ASC in microglia and astrocytes associated withAß plaques, in the absence of PRR described by others in glial cells. In addition, APP developed foci with clusters of extracellular ASC granules not spatiallyrelated to Aß plaques, which density correlated with the advanced age of mice and AD development. Clusters were associated withspecific astrocytes characterized by their enlarged ring-shaped process terminals, ASC content, and frequent perivascular location. Their possible implication in ASC clearance and propagation of inflammation is discussed.

A NOTCH3 homozygous nonsense mutation in familial Sneddon syndrome with pediatric stroke.

Sneddon syndrome is a rare disorder affecting small and medium-sized blood vessels that is characterized by the association of livedo reticularis and stroke. We performed whole-exome sequencing (WES) in 2 affected siblings of a consanguineous family with childhood-onset stroke and identified a homozygous nonsense mutation within the epidermal growth factor repeat (EGFr) 19 of NOTCH3, p.(Arg735Ter). WES of 6 additional cases with adult-onset stroke revealed 2 patients carrying heterozygous loss-of-function variants in putative NOTCH3 downstream genes, ANGPTL4, and PALLD. Our findings suggest that impaired NOTCH3 signaling is one underlying disease mechanism and that bi-allelic loss-of-function mutation in NOTCH3 is a cause of familial Sneddon syndrome with pediatric stroke.

Liver Growth Factor "LGF" as a Therapeutic Agent for Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive degenerative disorder and the most common cause of dementia in aging populations. Although the pathological hallmarks of AD are well defined, currently no effective therapy exists. Liver growth factor (LGF) is a hepatic albumin-bilirubin complex with activity as a tissue regenerating factor in several neurodegenerative disorders such as Parkinson's disease and Friedreich's ataxia. Our aim here was to analyze the potential therapeutic effect of LGF on the APPswe mouse model of AD. Twenty-month-old mice received intraperitoneal (i.p.) injections of 1.6 µg LGF or saline, twice a week during three weeks. Mice were sacrificed one week later, and the hippocampus and dorsal cortex were prepared for immunohistochemical and biochemical studies. LGF treatment reduced amyloid-ß (Aß) content, phospho-Tau/Tau ratio and the number of Aß plaques with diameter larger than 25 µm. LGF administration also modulated protein ubiquitination and HSP70 protein levels, reduced glial reactivity and inflammation, and the expression of the pro-apoptotic protein Bax. Because the administration of this factor also restored cognitive damage in APPswe mice, we propose LGF as a novel therapeutic tool that may be useful for the treatment of AD.

α-Secretase nonsense mutation (ADAM10 Tyr167*) in familial Alzheimer's disease.

BACKGROUND: The disintegrin metalloproteinase 10 (ADAM10) is the main α-secretase acting in the non-amyloidogenic processing of APP. Some ADAM10 gene variants have been associated with higher susceptibility to develop late-onset AD, though clear clinical-genetic correlates remain elusive. METHODS: Clinical-genetic and biomarker study of a first family with early- and late-onset AD associated with a nonsense ADAM10 mutation (p.Tyr167*). CSF analysis included AD core biomarkers, as well as Western blot of ADAM10 species and sAPPα and sAPPß peptides. We evaluate variant's pathogenicity, pattern of segregation, and further screened for the p.Tyr167* mutation in 197 familial AD cases from the same cohort, 200 controls from the same background, and 274 AD cases from an independent Spanish cohort. RESULTS: The mutation was absent from public databases and segregated with the disease. CSF Aß42, total tau, and phosphorylated tau of affected siblings were consistent with AD. The predicted haploinsufficiency effect of the nonsense mutation was supported by (a) ADAM10 isoforms in CSF decreased around 50% and (b) 70% reduction of CSF sAPPα peptide, both compared to controls, while sAPPß levels remained unchanged. Interestingly, sporadic AD cases had a similar decrease in CSF ADAM10 levels to that of mutants, though their sAPPα and sAPPß levels resembled those of controls. Therefore, a decreased sAPPα/sAPPß ratio was an exclusive feature of mutant ADAM10 siblings. The p.Tyr167* mutation was not found in any of the other AD cases or controls screened. CONCLUSIONS: This family illustrates the role of ADAM10 in the amyloidogenic process and the clinical development of the disease. Similarities between clinical and biomarker findings suggest that this family could represent a genetic model for sporadic late-onset AD due to age-related downregulation of α-secretase. This report encourages future research on ADAM10 enhancers.

Liver Growth Factor Induces Glia-Associated Neuroprotection in an In Vitro Model of Parkinson´s Disease.

Parkinson's disease is a neurodegenerative disorder characterized by the progressive death of dopaminergic (DA) neurons in the substantia nigra (SN), which leads to a loss of the neurotransmitter dopamine in the basal ganglia. Current treatments relieve the symptoms of the disease, but none stop or delay neuronal degeneration. Liver growth factor (LGF) is an albumin-bilirubin complex that stimulates axonal growth in the striatum and protects DA neurons in the SN of 6-hydroxydopamine-lesioned rats. Our previous results suggested that these effects observed in vivo are mediated by microglia and/or astrocytes. To determine if these cells are LGF targets, E14 (embryos from Sprague Dawley rats of 14 days) rat mesencephalic glial cultures were used. Treatment with 100 pg/mL of LGF up-regulated the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinases 1/2 (ERK1/2) and the cyclic AMP response element binding protein (CREB) phosphorylation in glial cultures, and it increased the microglia marker Iba1 and tumor necrosis factor alpha (TNF-alpha) protein levels. The treatment of E14 midbrain neurons with a glial-conditioned medium from LGF-treated glial cultures (GCM-LGF) prevented the loss of DA neurons caused by 6-hydroxy-dopamine. This neuroprotective effect was not observed when GCM-LGF was applied in the presence of a blocking antibody of TNF-alpha activity. Altogether, our findings strongly suggest the involvement of microglia and TNF-alpha in the neuroprotective action of LGF on DA neurons observed in vitro.

Novel mutations in the KCNJ10 gene associated to a distinctive ataxia, sensorineural hearing loss and spasticity clinical phenotype.

KCNJ10 encodes the inward-rectifying potassium channel (Kir4.1) that is expressed in the brain, inner ear, and kidney. Loss-of-function mutations in KCNJ10 gene cause a complex syndrome consisting of epilepsy, ataxia, intellectual disability, sensorineural deafness, and tubulopathy (EAST/SeSAME syndrome). Patients with EAST/SeSAME syndrome display renal salt wasting and electrolyte imbalance that resemble the clinical features of impaired distal tubular salt transport in Gitelman's syndrome. A key distinguishing feature between these two conditions is the additional neurological (extrarenal) manifestations found in EAST/SeSAME syndrome. Recent reports have further expanded the clinical and mutational spectrum of KCNJ10-related disorders including non-syndromic early-onset cerebellar ataxia. Here, we describe a kindred of three affected siblings with early-onset ataxia, deafness, and progressive spasticity without other prominent clinical features. By using targeted next-generation sequencing, we have identified two novel missense variants, c.488G>A (p.G163D) and c.512G>A (p.R171Q), in the KCNJ10 gene that, in compound heterozygosis, cause this distinctive EAST/SeSAME phenotype in our family. Electrophysiological characterization of these two variants confirmed their pathogenicity. When expressed in CHO cells, the R171Q mutation resulted in 50% reduction of currents compared to wild-type KCNJ10 and G163D showed a complete loss of function. Co-expression of G163D and R171Q had a more pronounced effect on currents and membrane potential than R171Q alone but less severe than single expression of G163D. Moreover, the effect of the mutations seemed less pronounced in the presence of Kir5.1 (encoded by KCNJ16), with whom the renal Kir4.1 channels form heteromers. This partial functional rescue by co-expression with Kir5.1 might explain the lack of renal symptoms in the patients. This report illustrates that a spectrum of disorders with distinct clinical symptoms may result from mutations in different parts of KCNJ10, a gene initially associated only with the EAST/SeSAME syndrome.

Anti-N-Methyl-D-Aspartate Encephalitis as Paraneoplastic Manifestation of Germ-Cells Tumours: A Cases Report and Literature Review.

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is the most common form of autoimmune encephalitis, caused by the interaction between an antibody and its target, located on glutamate receptor type N-methyl-D-aspartate (NMDA) of neuronal surface. There is a wide spectrum of clinical features starting by a viral-like prodrome, followed by symptoms such as psychosis, aggressive behaviour, memory loss, seizures, movement disorders, and autonomic instability. Up to 50% of the affected young female patients have germ-cells tumours as ovarian teratoma, making it essential to establish an early diagnosis through detection of specific antibodies in serum and cerebrospinal fluid (CSF). This retrospective observational study was performed in patients whom positive anti-NMDA receptor antibodies have been tested, associated with clinical manifestations that suggest autoimmune encephalitis and a germ-cell tumour confirmed by pathology. Six patients have tested positive for anti-NMDA receptor antibodies associated with a germ-cell tumour and clinical manifestations of autoimmune encephalitis. Management includes aggressive immunosuppression and surgical removal.

PLA2G6-associated neurodegeneration: New insights into brain abnormalities and disease progression.

INTRODUCTION: PLA2G6-associated neurodegeneration (PLAN) comprises a continuum of three phenotypes with overlapping clinical and radiologic features. METHODS: Observational clinical study in a cohort of infantile and childhood onset PLAN patients and genetic analysis of the PLA2G6 gene. We analysed chronological evolution in terms of age at onset and disease course through a 66-item questionnaire. We performed qualitative and quantitative assessment of MRI abnormalities and searched for clinical and radiological phenotype and genotype correlations. RESULTS: Sixteen PLAN patients (mean age: 10.2 years, range 3-33) were evaluated, with a median onset (years) of signs/symptoms as follows: neurological regression (1.5), oculomotor abnormalities (1.5), hypotonia (1.8), gait loss (2.2), pyramidal signs (3.0), axonal neuropathy (3.0), dysphagia (4.0), optic atrophy (4.0), psychiatric symptoms (4.0), seizures (5.9), joint contractures (6.0), dystonia (8.0), bladder dysfunction (13.0) and parkinsonism (15.0). MRI assessment identified cerebellar atrophy (19/19), brain iron deposition (10/19), clava hypertrophy (8/19) and T2/FLAIR hyperintensity of the cerebellar cortex (6/19). The mid-sagittal vermis relative diameter (MVRD) correlated with age at onset of clinical variants, meaning that the earlier the onset, the more severe the cerebellar atrophy. All patients harboured missense, nonsense and frameshift mutations in PLA2G6, including four novel variants. CONCLUSIONS: Cerebellar atrophy was a universal radiological sign in infantile and childhood onset PLAN, and correlated with the severity of the phenotype. Iron accumulation within the globus pallidum and substantia nigra was also a common and strikingly uniform feature regardless of the phenotype.

Clinical and genetical study of a familial form of REM sleep behavior disorder.

OBJECTIVE: We report a kindred with a genetic form of REM behaviour disorder (RBD) with autosomal dominant transmission. PATIENTS AND METHODS: Clinical, polysomnography study, genetic study and brain MRI were performed to evaluate the index patients. The genetic study included exome sequencing of the index cases that detected 60,869 variants in the individuals examined. RESULTS: The kindred has a RBD with autosomal dominant transmission starting in second decade of life. After filtering out the exome variants shared by two affected cases the pool of variants could be reduced to thirteen; one of them is in PVALB, a calcium-binding albumin protein present in gabaergic interneurons in the nervous system that inhibit the pyramidal cell during REM sleep. CONCLUSIONS: RBD can have a genetic origin. The results of the exome study in this kindred suggest that gabaergic circuits may be altered in patients with RBD. Further studies in this family or in other pedigrees with familial RBD may clear the role of this gene in this disorder.

RNA-Seq blood transcriptome profiling in familial attention deficit and hyperactivity disorder (ADHD).

We have carried an exploratory study by blood transcriptome to find RNA expression signatures in familial ADHD. Samples were collected from three cases with familial ADHD and their paired controls and evaluated by RNA-Seq. Transcriptome profiling identified 7 differentially expressed transcripts with a FDR <0.05 that were involved in pathways in Huntington's disease or axonal guidance signaling previously implicated in ADHD, and enriched for signal peptide, growth factor binding, and notably the lipid metabolism pathways. These findings show that blood transcriptome can have an associated signature and highlight a potential to use blood transcriptome to identify patterns of ADHD.

A novel ATTR L32V mutation causes familial amyloid polyneuropathy in a Bolivian family.

We report a new transthyretin (ATTR) gene c.272C>G mutation and variant protein, p.Leu32Val, in a kindred of Bolivian origin with a rapid progressive peripheral neuropathy and cardiomyopathy. Three individuals from a kindred with peripheral nerve and cardiac amyloidosis were examined. Analysis of the TTR gene was performed by Sanger direct sequencing. Neuropathologic examination was obtained on the index patient with mass spectrometry study of the ATTR deposition. Direct DNA sequence analysis of exons 2, 3, and 4 of the TTR gene demonstrated a c.272 C>G mutation in exon 2 (p.L32V). Sural nerve biopsy revealed massive amyloid deposition in the perineurium, endoneurium and vasa nervorum. Mass spectrometric analyses of ATTR immunoprecipitated from nerve biopsy showed the presence of both wild-type and variant proteins. The observed mass results for the wild-type and variant proteins were consistent with the predicted values calculated from the genetic analysis data. The ATTR L32V is associated with a severe course. This has implications for treatment of affected individuals and counseling of family members.

Liver Growth Factor (LGF) Upregulates Frataxin Protein Expression and Reduces Oxidative Stress in Friedreich's Ataxia Transgenic Mice.

Friedreich's ataxia (FA) is a severe disorder with autosomal recessive inheritance that is caused by the abnormal expansion of GAA repeat in intron 1 of FRDA gen. This alteration leads to a partial silencing of frataxin transcription, causing a multisystem disorder disease that includes neurological and non-neurological damage. Recent studies have proven the effectiveness of neurotrophic factors in a number of neurodegenerative diseases. Therefore, we intend to determine if liver growth factor (LGF), which has a demonstrated antioxidant and neuroprotective capability, could be a useful therapy for FA. To investigate the potential therapeutic activity of LGF we used transgenic mice of the FXNtm1MknTg (FXN)YG8Pook strain. In these mice, intraperitoneal administration of LGF (1.6 µg/mouse) exerted a neuroprotective effect on neurons of the lumbar spinal cord and improved cardiac hypertrophy. Both events could be the consequence of the increment in frataxin expression induced by LGF in spinal cord (1.34-fold) and heart (1.2-fold). LGF also upregulated by 2.6-fold mitochondrial chain complex IV expression in spinal cord, while in skeletal muscle it reduced the relation oxidized glutathione/reduced glutathione. Since LGF partially restores motor coordination, we propose LGF as a novel factor that may be useful in the treatment of FA.

Liver growth factor as a tissue regenerating factor in neurodegenerative diseases.

Liver growth factor (LGF) is a hepatic mitogen purified by our group in 1986. In the following years we demonstrated its activity both in "in vivo" and "in vitro" systems, stimulating hepatocytes mitogenesis as well as liver regeneration in several models of liver injury. Furthermore, we established its chemical composition (albumin-bilirubin complex) and its mitogenic actions in liver. From 2000 onwards we used LGF as a tissue regenerating factor in several models of extrahepatic diseases. The use of Liver growth factor as a neural tissue regenerator has been recently protected (Patent No US 2014/8,642,551 B2). LGF administration stimulates neurogenesis and neuron survival, promotes migration of newly generated neurons, and induces the outgrowth of striatal dopaminergic terminals in 6-hidroxydopamine-lesioned rats. Furthermore, LGF treatment raises striatal dopamine levels and protects dopaminergic neurons in hemiparkinsonian animals. LGF also stimulates survival of grafted foetal neural stem cells in the damaged striatum, reduces rotational behaviour and improves motor coordination. Interestingly, LGF also exerts a neuroprotective role both in an experimental model of cerebellar ataxia and in a model of Friedrich´s ataxia. Microglia seem to be the cellular target of LGF in the CNS. Moreover, the activity of the factor could be mediated by the stimulation of MAPK´s signalling pathway and by regulating critical proteins for cell survival, such as Bcl-2 and phospho-CREB. Since the factor shows neuroprotective and neurorestorative effects we propose LGF as a patented novel therapeutic tool that may be useful for the treatment of Parkinson´s disease and cerebellar ataxias. Currently, our studies have been extended to other neurological disorders such as Alzheimer's disease (Patent No: US 2014/0113859 A1).

Neuroprotective role of liver growth factor "LGF" in an experimental model of cerebellar ataxia.

Cerebellar ataxias (CA) comprise a heterogeneous group of neurodegenerative diseases characterized by a lack of motor coordination. They are caused by disturbances in the cerebellum and its associated circuitries, so the major therapeutic goal is to correct cerebellar dysfunction. Neurotrophic factors enhance the survival and differentiation of selected types of neurons. Liver growth factor (LGF) is a hepatic mitogen that shows biological activity in neuroregenerative therapies. We investigate the potential therapeutic activity of LGF in the 3-acetylpiridine (3-AP) rat model of CA. This model of CA consists in the lesion of the inferior olive-induced by 3-AP (40 mg/kg). Ataxic rats were treated with 5 µg/rat LGF or vehicle during 3 weeks, analyzing: (a) motor coordination by using the rota-rod test; and (b) the immunohistochemical and biochemical evolution of several parameters related with the olivo-cerebellar function. Motor coordination improved in 3-AP-lesioned rats that received LGF treatment. LGF up-regulated NeuN and Bcl-2 protein levels in the brainstem, and increased calbindin expression and the number of neurons receiving calbindin-positive projections in the cerebellum. LGF also reduced extracellular glutamate and GABA concentrations and microglia activation in the cerebellum. In view of these results, we propose LGF as a potential therapeutic agent in cerebellar ataxias.

Neuroprotective activity of peripherally administered liver growth factor in a rat model of Parkinson's disease.

Liver growth factor (LGF) is a hepatic mitogen purified some years ago that promotes proliferation of different cell types and the regeneration of damaged tissues, including brain tissue. Considering the possibility that LGF could be used as a therapeutic agent in Parkinson's disease, we analyzed its potential neuroregenerative and/or neuroprotective activity when peripherally administered to unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. For these studies, rats subjected to nigrostriatal lesions were treated intraperitoneally twice a week with LGF (5 microg/rat) for 3 weeks. Animals were sacrificed 4 weeks after the last LGF treatment. The results show that LGF stimulates sprouting of tyrosine hydroxylase-positive terminals and increases tyrosine hydroxylase and dopamine transporter expression, as well as dopamine levels in the denervated striatum of 6-OHDA-lesioned rats. In this structure, LGF activates microglia and raises tumor necrosis factor-alpha protein levels, which have been reported to have a role in neuroregeneration and neuroprotection. Besides, LGF stimulates the phosphorylation of MAPK/ERK1/2 and CREB, and regulates the expression of proteins which are critical for cell survival such as Bcl2 and Akt. Because LGF partially protects dopamine neurons from 6-OHDA neurotoxicity in the substantia nigra, and reduces motor deficits in these animals, we propose LGF as a novel factor that may be useful in the treatment of Parkinson's disease.

Effects of intravenous administration of human umbilical cord blood stem cells in 3-acetylpyridine-lesioned rats.

Cerebellar ataxias include a heterogeneous group of infrequent diseases characterized by lack of motor coordination caused by disturbances in the cerebellum and its associated circuits. Current therapies are based on the use of drugs that correct some of the molecular processes involved in their pathogenesis. Although these treatments yielded promising results, there is not yet an effective therapy for these diseases. Cell replacement strategies using human umbilical cord blood mononuclear cells (HuUCBMCs) have emerged as a promising approach for restoration of function in neurodegenerative diseases. The aim of this work was to investigate the potential therapeutic activity of HuUCBMCs in the 3-acetylpyridine (3-AP) rat model of cerebellar ataxia. Intravenous administered HuUCBMCs reached the cerebellum and brain stem of 3-AP ataxic rats. Grafted cells reduced 3-AP-induced neuronal loss promoted the activation of microglia in the brain stem, and prevented the overexpression of GFAP elicited by 3-AP in the cerebellum. In addition, HuUCBMCs upregulated the expression of proteins that are critical for cell survival, such as phospho-Akt and Bcl-2, in the cerebellum and brain stem of 3-AP ataxic rats. As all these effects were accompanied by a temporal but significant improvement in motor coordination, HuUCBMCs grafts can be considered as an effective cell replacement therapy for cerebellar disorders.

Querying phenotype-genotype relationships on patient datasets using semantic web technology: the example of Cerebrotendinous xanthomatosis.

BACKGROUND: Semantic Web technology can considerably catalyze translational genetics and genomics research in medicine, where the interchange of information between basic research and clinical levels becomes crucial. This exchange involves mapping abstract phenotype descriptions from research resources, such as knowledge databases and catalogs, to unstructured datasets produced through experimental methods and clinical practice. This is especially true for the construction of mutation databases. This paper presents a way of harmonizing abstract phenotype descriptions with patient data from clinical practice, and querying this dataset about relationships between phenotypes and genetic variants, at different levels of abstraction. METHODS: Due to the current availability of ontological and terminological resources that have already reached some consensus in biomedicine, a reuse-based ontology engineering approach was followed. The proposed approach uses the Ontology Web Language (OWL) to represent the phenotype ontology and the patient model, the Semantic Web Rule Language (SWRL) to bridge the gap between phenotype descriptions and clinical data, and the Semantic Query Web Rule Language (SQWRL) to query relevant phenotype-genotype bidirectional relationships. The work tests the use of semantic web technology in the biomedical research domain named cerebrotendinous xanthomatosis (CTX), using a real dataset and ontologies. RESULTS: A framework to query relevant phenotype-genotype bidirectional relationships is provided. Phenotype descriptions and patient data were harmonized by defining 28 Horn-like rules in terms of the OWL concepts. In total, 24 patterns of SWQRL queries were designed following the initial list of competency questions. As the approach is based on OWL, the semantic of the framework adapts the standard logical model of an open world assumption. CONCLUSIONS: This work demonstrates how semantic web technologies can be used to support flexible representation and computational inference mechanisms required to query patient datasets at different levels of abstraction. The open world assumption is especially good for describing only partially known phenotype-genotype relationships, in a way that is easily extensible. In future, this type of approach could offer researchers a valuable resource to infer new data from patient data for statistical analysis in translational research. In conclusion, phenotype description formalization and mapping to clinical data are two key elements for interchanging knowledge between basic and clinical research.

Secuenciación de genoma completo: un salto cualitativo en los estudios genéticos / Whole genome sequencing: a qualitative leap forward in genetic studies

Resumen. En estos momentos se encuentra en plena expansión la llamada secuenciación paralela o de siguiente generación -next generation sequencing (NGS)-, que establece un salto de varios órdenes de magnitud en la longitud de los fragmentos secuenciados y la rapidez de su secuenciación. La NGS permite la secuenciación de un genoma humano completo en el tiempo y el coste económico de secuenciar dos o tres genes grandes con la técnica de Sanger. Mediante la NGS se pasa de examinar genes específicos seleccionados mediante estudio del fenotipo a explorar genomas enteros de grupos humanos o de otras especies. Esto está permitiendo conocer no sólo cómo es un genoma individual, sino cómo cambia el genoma humano de persona a persona, cómo difieren los genomas entre diferentes grupos humanos, e incluso cómo difiere el genoma de un tumor respecto del genoma sano del huésped (AU)

Summary. At the present time the so-called parallel or next generation sequencing (NGS) technique is rapidly expanding and developing; this process establishes a jump by several orders of magnitude in the length of the fragments sequenced and the speed with which this sequencing is carried out. NGS allows a whole human genome to be sequenced in the same amount of time and with the same economic cost required to sequence two or three large genes using the Sanger technique. Use of NGS allows us to go from examining specific genes selected by studying the phenotype to exploring whole genomes of groups of humans or other species. This is making it possible to know not only what an individual genome is like but also how the human genome changes from one person to another, how genomes differ from one group of humans to another, and even how the genome differs in a tumour with respect to the healthy genome of the host (AU)