Fragile X syndrome (FXS) is a genetic disorder characterized by mild-to-moderate intellectual disability. The average IQ in males with FXS is under 55, while about two thirds of affected females are intellectually disabled. Physical features may include a long and narrow face, large ears, flexible fingers, and large testicles. About a third of those affected have features of autism such as problems with social interactions and delayed speech. Hyperactivity is common, and seizures occur in about 10%. Males are usually more affected than females.
David Gil Amaral is a professor of psychiatry at the University of California, Davis, United States, and since 1998 has been the research director at the M.I.N.D. Institute, an affiliate of UC Davis, engaged in interdisciplinary research into the causes and treatment of autism and related neurodevelopmental disorders. Amaral joined the UC Davis faculty as a professor in the Department of Psychiatry and the Center for Neuroscience and as an investigator at the California Regional Primate Research Center in 1991. Since 1995, he has been a professor of psychiatry in the UC Davis School of Medicine, with an appointment to the Center for Neuroscience.
The UC Davis MIND Institute is a research and treatment center affiliated with the University of California, Davis, with facilities located on the UC Davis Medical Center campus in Sacramento, California. The institute is a consortium of scientists, educators, physicians and parents dedicated to researching the causes of and treatments for autism spectrum disorders, fragile X syndrome, and other neurodevelopmental disorders. The director of the MIND institute is Dr. Leonard Abbeduto.
The heritability of autism is the proportion of differences in expression of autism that can be explained by genetic variation; if the heritability of a condition is high, then the condition is considered to be primarily genetic. Autism has a strong genetic basis. Although the genetics of autism are complex, autism spectrum disorder (ASD) is explained more by multigene effects than by rare mutations with large effects.
FMR1 is a human gene that codes for a protein called fragile X messenger ribonucleoprotein, or FMRP. This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function. Mutations of this gene can lead to fragile X syndrome, intellectual disability, premature ovarian failure, autism, Parkinson's disease, developmental delays and other cognitive deficits. The FMR1 premutation is associated with a wide spectrum of clinical phenotypes that affect more than two million people worldwide.
Intention tremor is a dyskinetic disorder characterized by a broad, coarse, and low-frequency tremor evident during deliberate and visually-guided movement. An intention tremor is usually perpendicular to the direction of movement. When experiencing an intention tremor, one often overshoots or undershoots one's target, a condition known as dysmetria. Intention tremor is the result of dysfunction of the cerebellum, particularly on the same side as the tremor in the lateral zone, which controls visually guided movements. Depending on the location of cerebellar damage, these tremors can be either unilateral or bilateral.
XXYY syndrome is a sex chromosome anomaly in which males have 2 extra chromosomes, one X and one Y chromosome. Human cells usually contain two sex chromosomes, one from the mother and one from the father. Usually, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The appearance of at least one Y chromosome with a properly functioning SRY gene makes a male. Therefore, humans with XXYY are genotypically male. Males with XXYY syndrome have 48 chromosomes instead of the typical 46. This is why XXYY syndrome is sometimes written as 48, XXYY syndrome or 48, XXYY. It affects an estimated one in every 18,000–40,000 male births.
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder most frequently seen in male premutation carriers of Fragile X syndrome (FXS) over the age of 50. The main clinical features of FXTAS include problems of movement with cerebellar gait ataxia and action tremor. Associated features include parkinsonism, cognitive decline, and dysfunction of the autonomic nervous system. FXTAS is found in Fragile X "premutation" carriers, which is defined as a trinucleotide repeat expansion of 55-200 CGG repeats in the Fragile X mental retardation-1 (FMR1) gene. 4-40 CGG repeats in this gene is considered normal, while individual with >200 repeats have full Fragile X Syndrome.
Huda Yahya Zoghbi, born Huda El-Hibri, is a Lebanese-born American geneticist, and a professor at the Departments of Molecular and Human Genetics, Neuroscience and Neurology at the Baylor College of Medicine. She is the director of the Jan and Dan Duncan Neurological Research Institute. She became the editor of the Annual Review of Neuroscience as of 2018.
Fragile X-associated Primary Ovarian Insufficiency (FXPOI) is the most common genetic cause of premature ovarian failure in women with a normal karyotype 46, XX. The expansion of a CGG repeat in the 5' untranslated region of the FMR1 gene from the normal range of 5-45 repeats to the premutation range of 55-199 CGGs leads to risk of FXPOI for ovary-bearing individuals. About 1:150-1:200 women in the US population carry a premutation. Women who carry an FMR1 premutation have a roughly 20% risk of being diagnosed with FXPOI, compared to 1% for the general population, and an 8-15% risk of developing the neurogenerative tremor/ataxia disorder (FXTAS). FMR1 premutation women are also at increased risk of having a child with a CGG repeat that is expanded to >200 repeats. Individuals with a full mutation, unlike the premutation, produce little to no mRNA or protein from the FMR1 gene and are affected with Fragile X syndrome.
Metadoxine, also known as pyridoxine-pyrrolidone carboxylate, is a drug used to treat chronic and acute alcohol intoxication. Metadoxine accelerates alcohol clearance from the blood.
Nagwa Abdel Meguid is an Egyptian geneticist and 2002 winner of the L’Oreal UNESCO Award for Women in Science for Africa and the Middle East. Her research has "identified several genetic mutations that cause common syndromes such as the fragile X syndrome and Autism".
Wendy K. Chung is an American clinical and molecular geneticist and physician. She is the Chair of the Department of Pediatrics at Boston Children's Hospital and is on the faculty at Harvard Medical School. She is the author of 700 peer-reviewed articles and 75 chapters and has won several awards as a physician, researcher, and professor. Chung helped to initiate a new form of newborn screening for spinal muscular atrophy which is used nationally and was among the plaintiffs in the Supreme Court case which banned gene patenting.
Uta Francke is a German-American physician-geneticist known for her accomplishments in mapping genes to specific chromosome locations and discovering the genes and underlying mutations responsible for Prader-Willi and Rett syndromes. Her work on detailed mapping of human chromosome laid the foundation of the Human Genome Project and discovery of many other rare genetic disorders. She is currently a professor of Genetics and Pediatrics Emerita at Stanford University. She has also served as a consultant to 23andMe Inc since 2007, and as a part-time employee from 2010-2013.
Leonard Abbeduto is a psychologist known for his research on individuals with neurodevelopmental disorders, including Fragile X syndrome, autism spectrum disorder, and Down syndrome, and factors that influence their linguistic development over the lifespan. He is the Tsakopoulos-Vismara Endowed Chair of Psychiatry and Behavioral Sciences at University of California, Davis. He serves as Director of Research at the Medical Investigation of Neurodevelopment Disorders (MIND) Institute, which was launched in 2001. Prior to his affiliation with the University of California, Davis, Abbeduto was the associate director for Behavioral Sciences at the Waisman Center at the University of Wisconsin-Madison.
Stephen T. Warren was an American geneticist and academic. He was the William Patterson Timmie Professor of Human Genetics and the Charles Howard Candler Chair of Human Genetics. He was the former Founding Chairman of the Department of Human Genetics at Emory University School of Medicine. He was an Investigator with the Howard Hughes Medical Institute from 1991 until 2002, when he resigned to found the Human Genetics department. Warren is well known for his work in the field of Human Genetics. His research was focused on the mechanistic understanding of fragile X syndrome, a leading cause of inherited developmental disability and autism. In 2020, Warren stepped down as department chair after 20 years in that position.
Robert K. Naviaux is an American physician-scientist who specializes in mitochondrial medicine and complex chronic disorders. He discovered the cause of Alpers syndrome, and was part of the team that reported the first mitochondrial DNA (mtDNA) mutation to cause genetic forms of autism. Naviaux proposed the cell danger response (CDR) and hyperpurinergia hypothesis for complex disorders in 2014 and directed the first FDA-approved clinical trial to study the safety and efficacy of the antipurinergic drug suramin as a new treatment for autism spectrum disorder (ASD).
Natalia Gomez-Ospina is a Colombian physician-scientist who studies genetic disorders and lysosomal storage disorders. She was born in Medellín, Colombia. She is an Assistant Professor of Pediatrics (Genetics) and of Pediatrics at Stanford University and works at Lucile Packard Children's Hospital. She is a member of Stanford Bio-X.
Severe intellectual disability-progressive spastic diplegia syndrome is a rare novel genetic disorder characterized by severe intellectual disabilities, ataxia, craniofacial dysmorphisms, and muscle spasticity. It is a type of autosomal dominant syndromic intellectual disability.
Merlin G. Butler is an American physician scientist and professor at the University of Kansas Medical Center's Departments of Psychiatry & Behavioral Sciences and Pediatrics. He is board-certified in Clinical Genetics and Clinical Cytogenetics and was inducted into the American College of Medical Genetics and Genomics in 1993 as a founding fellow. He has over 500 publications in peer-reviewed journals, numerous book chapters.
