Article Title: Klinefelter syndrome (KS): genetics, clinical phenotype and hypogonadism
Authors: Bonomi, Rochira, Pasquali, Balercia, Jannini, and Ferlin
Date of Publication: September 19, 2016
“Klinefelter Syndrome (KS) is characterized by an extreme heterogeneity in its clinical and genetic presentation. The relationship between clinical phenotype and genetic background has been partially disclosed; nevertheless, physicians are aware that several aspects concerning this issue are far to be fully understood. By improving our knowledge on the role of some genetic aspects as well as on the KS, patients’ interindividual differences in terms of health status will result in a better management of this chromosomal disease. The aim of this review is to provide an update on both genetic and clinical phenotype and their interrelationships.”
Article Title: Strategies to improve early diagnosis of Klinefelter syndrome
Authors: Alberto Ferlin
Date of Publication: October 2020
“Klinefelter syndrome is the most frequent chromosome disorder in men, but it is largely undiagnosed or receives a late diagnosis in adulthood. This condition is characterized by an extra X-chromosome: approximately 80%-90% of patients with Klinefelter syndrome have a 47,XXY karyotype, 10%-20% mosaicisms of two different genetic lines such as 47,XXY/46,XY, isochromosome X, and higher number of X chromosomes. Although our knowledge on this syndrome substantially improved in last years, the diagnostic rate is still low. It has been estimated that only 25% to 40% of subjects with 47,XXY Klinefelter syndrome are ever diagnosed. A prenatal diagnosis is made in 15–20% of these cases, 10% is diagnosed before puberty, 15% at puberty, and the remaining 50–60% of cases are diagnosed during adulthood, typically in the course of a fertility workup, with some cases diagnosed even after the age of 50 or 60 years. Variants with higher number of X chromosomes (48,XXXY and 49,XXXXY) have more severe phenotype and distinct clinical features, which leads to higher diagnostic rate than 47,XXY. This manuscript refers to the most common form 47,XXY syndrome and strategies to improve early and timely diagnosis.”
In 2015, the AXYS Board of Directors voted to approve the development of the AXYS Clinical and Research Consortium (ACRC). The two goals that AXYS defined at that time were to improve the availability and the quality of services to the X&Y variation community. As the ACRC grew, the original goals were refined to be as follows:
Make life easier for those seeking evaluation and treatment.
Bring consistency to treatment that is consensus and/or evidence-based.
Advance the overall X&Y variation field through coordinated efforts including research.
Bring clinical excellence to the field of X&Y variations.
Though each clinic operates independently, as members of a consortium, they collaborate with one another, share informational resources, and have the opportunity to participate in joint research projects.
In addition, AXYS organizes annual meetings of the consortium at which members meet to discuss topics important to the X&Y chromosome variation community. AXYS works to ensure that all families impacted by any of the chromosome variations have access to the best available evaluation and treatment or treatment recommendations.
Timeline of the ACRC
(Click on the year to see the accomplishments for that year.)
CME Course Title: Klinefelter Syndrome: Identifying, characterizing and managing an underdiagnosed condition with serious consequences
Course Directors: Hooman Sadri, MD, PhD and Stuart Howards, MD
Reviewed by the AXYS Clinic & Research Consortium (ACRC)
Date: October 2020
Have you unknowingly seen someone with Klinefelter Syndrome in your practice?
Chances are, you have. Klinefelter Syndrome (KS) is the most common sex chromosome disorder, occurring in approximately 1 out of every 600 male births. Yet an estimated 60 to 75% of those with KS will remain undiagnosed throughout their lifetimes.
Why does this matter?
It matters because KS is linked to significantly higher mortality rates and a range of physical, neurocognitive, and social/behavioral comorbidities as well as a lower quality of life and socioeconomic status. Some healthcare providers believe that delayed diagnosis can increase patient morbidity. And it matters because those with KS are getting lost in our healthcare system. Studies show that the majority of individuals with KS report being dissatisfied with their care. In addition, many with KS and their families find that their providers have outdated information about the condition, or little information at all. By learning more about the many facets of KS, providers across the healthcare system can work together to better treat and support those with this condition and their families.”
Article Title: The Expert in the Room: Parental Advocacy for Children with Sex Chromosome Aneuploidies
Authors: Richardson, Riggan, and Allyse
Date of Publication: November 2, 2020
“Owing to fragmentation in the medical system, many parents of children with disabilities report taking on a care coordinator and advocate role. The parental advocacy and care coordination requirements are further amplified in this population because of a lack of awareness about sex chromosome aneuploidies (SCAs) in medical and social services settings, as well as the complex needs of affected children. This burden disproportionately affects mothers and low-resource families as a result of gendered ideas of parenthood and social stratification in resource access. The aim of this study is to understand the unique parental burdens of SCAs and family support needs.”
Article Title: Metabolic and cardiovascular risk factors in Klinefelter syndrome
Authors: Spaziani and Radicioni
Date of Publication: June 2020
“Klinefelter syndrome (KS), which normally presents with a 47,XXY karyotype, is the most common sex chromosome disorder in males. It is also the most common genetic cause of male infertility. KS subjects are typically tall, with small and firm testes, gynecomastia, broad hips, and sparse body hair, although a less evident presentation is also possible. KS is also characterized by a high prevalence of hypogonadism, metabolic syndrome (MetS) and cardiovascular disease. The aim of this article is to systematically review metabolic and the cardiovascular risk factors in KS patients. Hypogonadism has an important role in the pathogenesis of the changes in body composition (particularly visceral obesity) and hence of insulin resistance and MetS, but the association between KS and MetS may go beyond hypogonadism alone. From childhood, KS patients may show an increase in visceral fat with a reduction in lean body mass and an increase in glucose and impaired fat metabolism. Their increased incidence of congenital anomalies, epicardial adipose tissue, and thromboembolic disease suggests they have a higher risk of cardiovascular disease. There is conflicting evidence on the effects of testosterone therapy on body composition and metabolism.”
Article Title: Minipuberty in Klinefelter syndrome: Current status and future directions
Authors: Aksglaede, Davis, Ross, and Juul
Date of Publication: June 2020
“Klinefelter syndrome is highly underdiagnosed and diagnosis is often delayed. With the introduction of non-invasive prenatal screening, the diagnostic pattern will require an updated description of the clinical and biochemical presentation of infants with Klinefelter syndrome. In the first months of life, the hypothalamic–pituitary–gonadal (HPG)-axis is transiently activated in healthy males during the so-called minipuberty. This period represents a “window of opportunity” for evaluation of the HPG-axis before puberty and without stimulation tests. Infants with Klinefelter syndrome present with a hormonal surge during the minipuberty. However, only a limited number of studies exist, and the results are contradictory. Further studies are needed to clarify whether infants with Klinefelter syndrome present with impaired testosterone production during the minipuberty. The aim of this review is to describe the clinical and biochemical characteristics of the neonate and infant with Klinefelter syndrome with special focus on the minipuberty and to update the clinical recommendations for Klinefelter syndrome during infancy.”
Article Title: Psychological functioning, brain morphology, and functional neuroimaging in Klinefelter syndrome
Authors: Skakkebæk, Gravholt, Chang, Moore, and Wallentin
Date of Publication: June 2020
“Klinefelter syndrome (KS; 47,XXY) impacts neurodevelopment and is associated with an increased risk of cognitive, psychological and social impairments, although significant heterogeneity in the neurodevelopmental profile is seen. KS is characterized by a specific cognitive profile with predominantly verbal deficits, preserved function in non-verbal and visuo-spatial domains, executive dysfunction and social impairments, and by an increased vulnerability toward psychiatric disorders. The neurobiological underpinnings of the observed neuropsychological profile have not been established. A distinct pattern of both global and regional brain volumetric differences has been demonstrated in addition to preliminary findings of functional brain alterations related to auditory, motor, language and social processing. When present, the combination of cognitive, psychological and social challenges has the potential to negatively affect quality of life. This review intends to provide information and insight to the neuropsychological outcome and brain correlates of KS. Possible clinical intervention and future directions of research will be discussed.”
Article Title: Executive function in XXY: Comparison of performance-based measures and rating scales
Authors: Janusz, Harrison, C. Boada, Cordeiro, Howell, Tartaglia, and R. Boada
Date of Publication: June 2020
“Few studies have systematically assessed executive functioning (EF) skills in boys with XXY, and these are limited by small samples and restricted EF assessment. This study used a broader battery of performance-based measures as well as parent-rating scales of EF in 77 boys and adolescents with XXY (mean age = 12.5 years), recruited from a clinical trial and an outpatient clinic. Exploratory factor analyses were used to create EF domains from performance-based measures, and similar domains were measured using the Behavior Rating Inventory of Executive Function and Conners Parent-Rating Scales. The boys with XXY showed a distinct EF profile, with the greatest deficit in attention and more moderate deficits in working memory, switching, and planning/ problem solving. Parent ratings showed similar challenges, as well as impaired inhibition. Independent sample t-tests showed no difference on performance measures between boys diagnosed or not diagnosed with attention-deficit/hyperactivity disorder (ADHD), although parents of boys diagnosed with ADHD reported more difficulties. There were no differences on performance-based tests between those diagnosed pre- and postnatally, although parents of postnatally diagnosed boys reported more metacognitive problems. Language deficits, cognition, and socio-economic status did not account for EF deficits.”