The 49,XXXXY syndrome. Clinical and psychological follow-up data

The behavioral profile of 49,XXXXY and the potential impact of testosterone replacement therapy

PURPOSE

49,XXXXY (1:85,000-100,000) is a rare sex chromosome aneuploidy that often presents with complex musculoskeletal abnormalities, decreased cognitive capabilities, speech and language dysfunction, and behavioral complications. Hormonal replacement therapy, or testosterone replacement therapy, is associated with improved neurodevelopmental and behavioral outcomes in males with 49,XXXXY. Two forms of testosterone replacement therapy, early hormonal treatment (EHT) and hormonal booster therapy (HBT), are associated with improved neurodevelopmental and behavioral outcomes in these boys. This study investigates the impact of EHT and HBT on behavioral symptoms in males with 49,XXXXY.

METHODS

A total of 59 individuals were divided into 4 groups: 19 no testosterone (no-T), 23 EHT, 6 HBT, and 11 EHT and HBT. An analysis of variance examined group differences on the Child Behavior Checklist and the Behavior Rating Inventory of Executive Function ranging from 5 to 18 years.

RESULTS

Although no differences were identified on the Behavior Rating Inventory of Executive Function, the 3 hormonal replacement therapy groups presented with decreased complications on numerous variables on the Child Behavior Checklist; these include somatic complaints (P = .0095), somatic problems (P = .041), internalizing problems (P = .034), externalizing problems (P = .0001), and withdrawn/depression (P = .025).

CONCLUSION

This study presents evidence that HBT may be a beneficial treatment for individuals with 49,XXXXY.

Speech and language development in children with 49,XXXXY syndrome

49,XXXXY is the rarest X and Y chromosomal variation and is frequently characterized by expressive and receptive language dysfunction, low muscle tonus, and intellectual deficits. Due to the low incidence of this disorder, comprehensive studies analyzing the specific aspects of the speech and language phenotype in these boys have been uncommon. This is the first in-depth investigation of the speech and language profiles in a large cohort of boys with 49,XXXXY. Based on the clinical judgment of speech and language pathologists, there was an increased incidence (91.8%) of Childhood Apraxia of Speech (CAS), which has not been previously described in this disorder. In preschool boys, some significant differences were demonstrated between boys who received early hormonal treatment (n = 16) and untreated boys (n = 4) on the language scales (p = .047) on the Bayley Scales of Infants and Toddlers, as well as significant differences between treated (n = 13) and untreated boys (n = 8) on the Expressive One Word Picture Vocabulary Test (p = .008). No significant differences between treatment groups were found in school age children, however, treated groups demonstrated less discrepancies between expressive and receptive language. More research and larger samples are needed to determine the extent of the impact of testosterone treatment on boys with 49,XXXXY. This study identifies CAS as a potential explanation for the significant expressive language dysfunction and subsequent behavioral dysfunction. These findings may assist in facilitating more targeted treatment and improved outcomes for boys with 49,XXXXY.

Behavioral phenotype of 49,XXXXY syndrome: Presence of anxiety-related symptoms and intact social awareness

49,XXXXY is a rare X and Y chromosome variation that occurs in 1:85,000 to 1:100,000 live male births and is notable for variable motor, speech, and behavioral deficits. Case studies have described boys with this disorder as shy, impulsive, and aggressive with low frustration tolerances; however, previous studies have been limited due to cohort size. This study reports on the largest cohort of boys with 49,XXXXY to date with an emphasis on the prevalence of anxiety-related symptoms and sociability from preschool to adolescence. The Child Behavior Checklist, Behavior Rating Inventory of Executive Function, 2nd edition, and Social Responsiveness Scale, 2nd edition were completed by parents on a cohort of 69. The cohort demonstrated deficits in social cognition and communication beginning in preschool, however, presented with consistent social awareness and motivation for social activities not previously appreciated in this disorder. In addition, signs of anxiety presented during preschool years and increased in severity with age, particularly in internalizing problems. Boys with 49,XXXXY presented with wide behavioral variability across all ages and domains. Further research into the potential influences of culture, birth order, biological treatment, and frequency of services is needed to better define the behavioral phenotype of children with this disorder.

Case report: 49, XXXXY syndrome and high myopia

49, XXXXY karyotype syndrome has been thought of as a variant of Klinefelter's syndrome. It has an incidence of between 1/85 000 to 1/100 000 live births. Typical clinical features include coarse faces, skeletal abnormalities, hypogenitalism and severe learning difficulties. Common ocular features include hypertelorism, epicanthic folds and up-slanting palpebral apertures. Here we report a case of high myopia and its successful correction leading to a positive personality change in one such patient. We advocate full ophthalmic examination, under anaesthesia if necessary, and a trial of refractive correction, even in children thought unlikely to tolerate such.

Neurologic aspects of 49,XXXXY syndrome

49,XXXXY syndrome is a rare sex chromosome aneuploidy syndrome characterized by mental retardation, severe speech impairment, craniofacial abnormalities, multiple skeletal defects, and genital abnormalities. We describe a 13-year-old boy with 49,XXXXY syndrome, language impairment, seizures, and left-hemisphere magnetic resonance imaging abnormalities and review the distinctive neurologic, cognitive, and behavioral phenotypes associated with this disorder. Finally, we discuss testosterone supplementation in the treatment of this syndrome.

Prenatal sonographic diagnosis of the 49,XXXXY syndrome

The 49,XXXXY syndrome is a rare sex chromosome anomaly with an approximate incidence of 1 in 85,000 male live births. The diagnosis is usually ascertained postnatally by the association of mental retardation, variable growth deficiency, Down syndrome-like facial dysmorphy, hypogenitalism and other malformations, especially involving the heart and skeleton. Prenatal diagnosis of the pentasomy 49,XXXXY is generally fortuitous and sonographic features have rarely been described in the literature. We report here on two cases of 49,XXXXY syndrome diagnosed prenatally because of sonographic abnormalities. In the first, amniocentesis was performed at 26 weeks' gestation for polyhydramnios, unilateral clubfoot and micropenis. In the second, a karyotype was carried out on chorionic villi at 13 weeks' gestation for cystic hygroma. These observations and the six previously reported cases demonstrate that cystic hygroma in first or second trimester of pregnancy may be associated with sex chromosome aneuploidy other than Turner syndrome. Moreover, they emphasize the importance of detailed sonographic examination in the second trimester, as small penis and abnormal posturing of the lower extremities are very suggestive of the 49,XXXXY syndrome.

Language in mental retardation: Individual and syndromic differences, and neurogenetic variation 1Based on a keynote presentation at the Third European Conference on Psychological Theory and Research in Mental Retardation, Geneva, September 1st, 2000

Predominantly non-etiological conceptions have dominated the field of mental retardation (MR) since the discovery of the genetic etiology of Down syndrome (DS) in the sixties. However, contemporary approaches are becoming more etiologically oriented. Important differences across MR syndromes of genetic origin are being documented, particularly in the cognition and language domains, differences not explicable in terms of psychometric level, motivation, or other dimensions. This paper highlights the major difficulties observed in the oral language development of individuals with genetic syndromes of mental retardation. The extent of inter- and within-syndrome variability are evaluated. Possible brain underpinnings of the behavioural differences are envisaged. Cases of atypically favourable language development in MR individuals are also summarized and explanatory variables discussed. It is suggested that differences in brain architectures, originating in neurological development and having genetic origins, may largely explain the syndromic as well as the individual within-syndrome variability documented. Lastly, the major implications of the above points for current debates about modularity and developmental connectionism are spelt out.

49,XXXXY: a distinct phenotype. Three new cases and review

Over 100 cases of 49,XXXXY syndrome have been published to date. Classic findings include radioulnar synostosis, hypogonadism, and mental retardation. The majority of reported cases have not distinguished the 49,XXXXY syndrome from Klinefelter syndrome (47,XXY), and these patients are frequently labelled as having Klinefelter syndrome or as being a "Klinefelter variant." Because of distinct clinical features, we delineate the 49,XXXXY syndrome as separate from Klinefelter syndrome, and emphasise the prevalence of congenital heart defects. We also report three new cases of 49,XXXXY syndrome and briefly discuss patient management.

A PET study of Turner's syndrome: effects of sex steroids and the X chromosome on brain

Women with Turner's syndrome (TS) allow us to study the neurobiological associates of cognitive and behavioral abnormalities because they lack one/part of one X chromosome, and endogenous estrogen. We studied 13 healthy controls (mean age +/- SD, 28 +/- 6 years) and 16 TS subjects (mean age +/- SD, 26 +/- 6 years). We measured cognitive abilities using neuropsychological tests, and cerebral metabolic rates for glucose with positron emission tomography. Compared to controls, TS subjects had significant absolute hypermetabolism in most brain areas; however, normalized metabolism was significantly lower in TS subjects than controls in the insula and association neocortices bilaterally, and there were significant differences in functional metabolic associations of brain region pairs originating in occipital cortex bilaterally, and within the right hemisphere. There were significant correlations between right-left cognitive and metabolic asymmetries in the TS group. Also, within TS a preliminary analysis demonstrated "X chromosome dosage" effects in language ability and left temporal metabolism, asymmetry of right-left test scores, and parietal metabolism. We hypothesize that within TS: i) generalized brain hypermetabolism reflects global abnormalities in neuron packing; ii) neuronal abnormalities occur in association neocortex that differ in nature or extent from whole brain and are associated with significant differences in normalized metabolism; iii) cognitive deficits are related to brain metabolic abnormalities; and iv) social-behavioral problems may be related to abnormalities of brain metabolism. Moreover, in human brain the X chromosome involved in development of the association neocortices.

The effects of sex steroids, and the X chromosome, on female brain function: a study of the neuropsychology of adult Turner syndrome

Sex steroids and the X chromosome can independently affect cognitive abilities. Because subjects with Turner syndrome (TS) have gonadal aplasia, and various alterations in X chromosome structure and number, they provide a model to study the effects of sex steroids and of the X chromosome on human brain function. We used neuropsychological tests to study the cognitive abilities of 18 TS adults and 19 age/sex matched healthy controls. Nine TS subjects were mosaic for the 45,X karyotype, and 9 were non-mosaic 45,X (full TS). The TS group as a whole, compared to controls, had (i) significantly lower scores in tests of language and visual-spatial function, attention and memory, and (ii) a significantly greater discrepancy between verbal and performance scores. Mosaic TS subjects were intermediate between full TS and controls in some tests of verbal ability, but did not differ significantly from controls in others. Visuospatial ability was significantly lower than controls in both mosaic and full TS. Within the mosaic TS group, there was a significant negative correlation between visuospatial ability and % lymphocytes having a 45,X karyotype. Memory test scores were reduced independently of "X chromosome dosage" in all TS subjects. We conclude that in humans, the X chromosome is involved in development of both cerebral hemispheres, but moreso of the association neocortices. Also, sex steroids may modulate this effect--particularly in hippocampus.

49,XXXXY syndrome: behavioural and developmental profiles

Behavioural, psychological, and cognitive profiles of three cases, including a 5 year old male with a 49,XXXXY karyotype and a (3;15) translocation, a 9 year old male with a 49,XXXXY karyotype, and a 32 year old male with 48,XXXY/49,XXXXY mosaicism, are presented. Significant behavioural problems were seen in the two older patients. The degree of mental retardation and impairment of language abilities were shown to be more severe in the older subjects as well. These findings are discussed with respect to the effects of the X chromosome on brain development.

Parental origin of chromosomal nondisjunction in a 49,XXXXY male using recombinant-DNA techniques

We have analyzed the origin, in a patient with 49,XXXXY, of the four X-chromosomes by means of recombinant DNA techniques. We found a maternal origin of the four X-chromosomes due to non-disjunctions in the first and second meiotic divisions.