{"id":1654,"date":"2026-08-14T00:13:09","date_gmt":"2026-08-13T22:13:09","guid":{"rendered":"https:\/\/kleefstrasyndrome.com\/?page_id=1654"},"modified":"2026-08-14T23:56:11","modified_gmt":"2026-08-14T21:56:11","slug":"kleefstra-clinic-chb","status":"publish","type":"page","link":"https:\/\/kleefstrasyndrome.com\/en\/kleefstra-clinic-chb\/","title":{"rendered":"Kleefstra Syndrome Clinic in America"},"content":{"rendered":"
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Specialized Clinic for Kleefstra Syndrome at Boston Children's Hospital<\/h2>\n\n\n\n

For families living with a rare syndrome, one of the biggest problems is not just the diagnosis itself. It is also the fact that care is often fragmented among many different specialists, who may have little or no previous experience with the specific condition. In the case of Kleefstra syndrome, one of the specialized centers established internationally to gather clinical expertise and research around the syndrome operates in Boston Children\u2019s Hospital<\/strong>, in Boston, United States.<\/p>\n\n\n\n

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Visit the website<\/a><\/div>\n<\/div>\n<\/div>\n\n\n\n
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Book an Appointment<\/a><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
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\u0397 Kleefstra Syndrome Clinic<\/strong> It does not only have a clinical role. At the same time, it constitutes a hub where the monitoring of individuals with Kleefstra is connected with natural history studies, neurodevelopmental assessment, genetic research, and the preparation of the field for future clinical trials. Its creation was also supported by the IDefine organization, which had set as one of its main goals the establishment of a central point where families could turn to professionals with accumulated experience in the syndrome.<\/p>\n\n\n\n

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A team that knows Kleefstra<\/h2>\n\n\n\n

The value of a specialized clinic for such a rare syndrome lies primarily in the concentration of experience. Kleefstra can affect many different systems and the clinical picture varies significantly from person to person. Neurodevelopmental difficulties, epilepsy, sleep disorders, hearing problems, cardiac or renal findings, gastrointestinal difficulties, and mental health issues do not present in the same way or with the same severity in everyone.<\/p>\n\n\n\n

In a previous presentation of the clinic, Boston Children\u2019s described that patients were evaluated, among others, by the pediatric neurologist Siddharth Srivastava<\/strong> and the geneticist Anne O\u2019Donnell-Luria<\/strong>, with monitoring for potential complications such as mental health issues, hearing loss, seizures, kidney, and heart problems. In 2023, the hospital reported that the clinic already had experience with approximately 50\u201360 patients. This number refers to that time period and should not be considered the current patient count.<\/p>\n\n\n\n

The current research team of the Kleefstra Syndrome Clinic includes Siddharth Srivastava as principal investigator and, among others, Maya Chopra, Anne O\u2019Donnell-Luria, Jonathan Lipton and Joe Kossowsky, as well as the genetic counselor and research manager Zo\u00eb Frazier<\/strong>.<\/p>\n\n\n\n

This interdisciplinary approach is of particular importance in Kleefstra. A physician may be excellent in their own field, but in an extremely rare disorder it is difficult to gain experience from enough patients on their own to recognize its entire spectrum. In a specialized center, by contrast, the knowledge gained from each family is gradually added to the overall picture of the syndrome.<\/p>\n<\/div><\/div>\n\n\n\n

From clinical experience to a better understanding of the syndrome<\/h2>\n\n\n\n

This is already evident in the publications that have emerged from the clinic. In 2025, Boston Children\u2019s researchers published a retrospective study 65 individuals with confirmed Kleefstra syndrome<\/strong> that had been evaluated at the Kleefstra Clinic. It was one of the most important patient clinical series studied to date.<\/p>\n\n\n\n

In this group, the 54% had a pathogenic variant in its sequence EHMT1<\/em>, while the rest had smaller or larger deletions in the 9q34 region. The study recorded not only the most frequent characteristics but also lesser-known manifestations, helping to broaden our picture of the syndrome's spectrum. Among the findings were autism spectrum disorders, epilepsy, congenital heart disease, hearing loss, and constipation, while smaller subgroups with more severe motor impairment or drug-resistant epilepsy were also recorded.<\/p>\n\n\n\n

The significance of this data is not that it can predict what will happen to a specific child. Instead, they highlight how heterogeneous<\/strong> It is Kleefstra. Two people with the same diagnosis can have quite different needs, which makes personalized monitoring even more important.<\/p>\n\n\n\n

In 2026, a team with significant participation from Boston Children's researchers also published the first systematic data on developmental profile of infants and toddlers with Kleefstra syndrome<\/strong>, adding information for an age period for which until recently there was limited organized data.<\/p>\n\n\n\n

At the same time, members of the Boston Children's team also participated in the publication of international clinical guidelines for Kleefstra syndrome in 2026<\/strong>, which demonstrates the connection between systematic data collection and the effort to translate this knowledge into better organized care.<\/p>\n\n\n\n

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The new natural history study and preparation for clinical trials<\/h2>\n\n\n\n

Special interest is held by the research activity currently underway. The Kleefstra Syndrome Clinic is participating in the initiative ACTION \u2013 Accelerating Clinical Trial Readiness Innovations for Monogenic Neurodevelopmental Disorders<\/strong> and has launched a three-year, longitudinal natural history study of Kleefstra syndrome.<\/p>\n\n\n\n

The goal of such a study is not to test a treatment. It is to understand with much greater precision how the syndrome evolves over time<\/strong> and which characteristics can be measured reliably.<\/p>\n\n\n\n

This is crucial for the next stage of the research. In order for a potential gene, RNA, or drug therapy to eventually be evaluated, researchers must first know exactly what to measure: which neurodevelopmental function can change, which marker is stable enough, which change truly matters to the patient, and over what timeframe it can be observed.<\/p>\n\n\n\n

The current Boston Children's study therefore aims both to better describe the clinical, molecular, and neurodevelopmental spectrum of Kleefstra and to search for biomarkers and appropriate outcome measures for future interventional studies<\/strong>.<\/p>\n\n\n\n

According to the clinic's official information, individuals aged 2 to 21 years old<\/strong> diagnosed with Kleefstra syndrome. Three annual visits with the research team are scheduled, which can take place either in person or remotely. At each visit, neurobehavioral assessments and questionnaires are conducted and, with the relevant consent, the team may review medical records from the local facilities where the participant is monitored.<\/p>\n\n\n\n

There are also optional parts of the study, such as research EEG, blood draw, Fitbit use at home for up to seven days, and providing photographs<\/strong>. Participation in these individual components is not the same thing as clinical care and should not be confused with a therapeutic clinical trial.<\/p>\n<\/div><\/div>\n\n\n\n

Sleep, behavior, and loss of skills<\/h2>\n\n\n\n

Another area in which the Boston Children's team has heavily invested is sleep and circadian rhythms. Previous research activity by the clinic examined the relationship of EHMT1<\/em> with the molecular mechanisms of sleep and tried to better understand sleep disorders that may precede significant behavioral changes or loss of already acquired skills<\/strong> in some individuals with Kleefstra. This specific study is no longer accepting new participants.<\/p>\n\n\n\n

This research is important because adolescence and the transition to adulthood are, for some families, a particularly difficult period. However, not all individuals with Kleefstra show such deterioration, and the course can vary significantly. Clinical experience itself has highlighted this great variability.<\/p>\n\n\n\n

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Can a family from Greece contact the clinic?;<\/h2>\n\n\n\n

Yes. The official website of Boston Children's provides the ability Request an Appointment<\/strong> and Get a Second Opinion<\/strong>, while providing a separate contact number for patients outside the United States. The Kleefstra Syndrome Clinic is located at Boston Children\u2019s Hospital, 300 Longwood Avenue, Boston, Massachusetts<\/strong>. The clinic number is +1 617-355-3645<\/strong>, while for international patients it is mentioned +1 617-355-5209<\/strong>.<\/p>\n\n\n\n

For families specifically interested in the current research study, Boston Children\u2019s lists as contact information the +1 617-919-7370<\/strong> and the email KleefstraSyndromeClinic@childrens.harvard.edu<\/a><\/strong>.<\/p>\n\n\n\n

In its informational material for families, IDefine recommends that prior to an appointment, the following should be available: genetic result confirming the diagnosis<\/strong>, the most recent neurological and genetic evaluation and, if available, recent cognitive or psychological assessments. Special emphasis is placed on the genetic result itself.<\/p>\n\n\n\n

For a family from Greece, communicating with the center does not necessarily mean that a trip to Boston is required immediately. The first step can be sending the necessary information and contacting the clinic to clarify whether a clinical appointment, a second opinion, or potential participation in research is indicated. The prerequisites, cost, and insurance coverage of the clinical evaluation must always be confirmed directly with Boston Children\u2019s.<\/p>\n<\/div><\/div>\n\n\n\n

Why a clinic like this matters<\/h2>\n\n\n\n

The Kleefstra Syndrome Clinic does not currently offer a treatment that corrects the cause of the syndrome. Its importance lies elsewhere: It gathers experience that would otherwise be scattered throughout the world<\/strong>.<\/p>\n\n\n\n

Every well-documented clinical evaluation, every natural history study, and every systematic registry helps answer questions that have remained unanswered for years: what is the true spectrum of Kleefstra? Which manifestations require closer monitoring? How do needs change from infancy to adulthood? And, most importantly, how will we be able to tell in the future if a new treatment truly alters the course of the disease?;<\/p>\n\n\n\n

With the research for EHMT1<\/em> as it now gradually transitions from describing the syndrome to developing potential therapeutic strategies, the existence of well-characterized patient groups and reliable natural history data becomes even more important. The Kleefstra Syndrome Clinic at Boston Children's is currently one of the centers systematically contributing to this transition.<\/p>\n\n\n\n

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Sources<\/h3>\n\n\n\n
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  • Boston Children\u2019s Hospital \u2013 Kleefstra Syndrome Clinic: Research & Innovation.<\/strong> Official information about the research team, the current ACTION natural history study, and contact details.<\/li>\n\n\n\n
  • Frazier ZJ et al. Novel Phenotypes and Genotype-Phenotype Correlations in a Large Clinical Cohort of Patients With Kleefstra Syndrome. Clinical Genetics, 2025.<\/strong> Study of 65 individuals evaluated at the Kleefstra Syndrome Clinic.<\/li>\n\n\n\n
  • Yue SL et al. The Infant and Toddler Developmental Profile of Kleefstra Syndrome. American Journal of Medical Genetics Part A, 2026. Boston Children\u2019s Answers \u2013 Cracking the code on Kleefstra syndrome: It takes a community.<\/strong> Presentation of the clinical and research work of the clinic.<\/li>\n\n\n\n
  • IDefine \u2013 Family Resource Packet.<\/strong> Practical information for families preparing for communication\/appointments with the clinic.<\/li>\n<\/ul>\n<\/div><\/div>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"

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