XYY males

CONTENTS

Introduction	5
The name XYY males?	7
How frequent is XYY?	7
What is the cause of XYY?	7
What is the cause of the chromosome aberration XYY?	8
Does a newborn boy with XYY present any signs of this?	8
How is the development of these boys during childhood?	8
Are XYY boys of average intelligence?	9
How do they manage at school?	10
Do they have increased risk of any diseases?	10
How is the height growth?	11
How is the physical sexual development?	11
How is development of sexual libido and potency?	11
Are XYY males able to have children?	12
Do XYY males marry?	13
Should XYY males have sex hormone?	13
How about occupation and work stability?	13
Is XYY a disease?	14
Is there an increased risk of getting mentally ill?	14
Should parents have full information?	15
Should XYY males have fully detailed information?	15
What kind of information should be given to parents, with an XYY foetus diagnosed prenatally?	17
Should the public have information about XYY males?	17
XYY contact groups	18
Literature about XYY males	19

Introduction

This booklet was written and published in the light of a tremendous need for further information about XYY males.

It is in no way an attempt of giving a complete description of all aspects of XYY males.

The booklet was written in order to give a better information to XYY boys and their parents as well as to adult XYY males, but it is also our hope that it will be read by genetic counsellors, physicians, teachers and others who come into contact with XYY boys and adult XYY males. More information on all levels will, however, first and foremost be valuable to XYY males and their relatives.

Publication by the Turner Center in Risskov, Denmark, should be seen as part of the work in this center with information, counselling and research concerning Turner and triple-X females, Klinefelter and XYY males.

Johannes Nielsen

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Klinefelter's syndrome with an extra X-chromosome (47,XXY) and Turner's syndrome with lack of X-chromosome material (45,X) have their names after the physicians who first described the syndromes in 1942 and 1937, respectively. Since 1960 geneticists have given new names to chromosome aberrations from the chromosome constitution and not as previously from the name of the person who first described the chromosome aberration.

When Sandberg and co-wokers in 1961 found the chromosome constitution 47,XYY, the name became XYY males in accordance with triple-X women with the chromosome constitution 47,XXX as first described by Jacobs and Strong in 1959.

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XYY is found in approximately 1 per 1,000 men. Thus in Denmark with a population of 5 mill. there are approximately 3,000 XYY males.

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Males usually have only one X and one Y, that is the chromosome constitution 46,XY. Males with XYY have two Y chromosomes (47,XYY). In rare cases there is a combination of Klinefelter's syndrome and XYY with the chromosome constitution 48,XXYY.

The chromosome constitution 47,XYY is found in approximately 80% of males with double Y. In 10% there is both a double X and a double Y, that is the above mentioned chromosome constitution 48,XXYY~ and in the last 10% a so-called chromosome mosaicism with normal chromosome constitution 46,XY in part of the cells and 47,XYY in the rest.

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Today we know no definite causes of the chromosome aberration which leads to XYY, that is an abnormal partition (a so-called non-disjunction) of the Y chromosome leading to two instead of one Y chromosome in the cells.

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No! Boys with XYY are usually quite normally developed at birth with normal birth weight and length without any physical abnormalities.

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Boys with XYY are often more physically active than their brothers, and if this activity is well accepted and canalised out in play, sport and other physical activities together with the parents and together with other children, this condition is in no way negative.

These boys have a tendency to a somewhat delayed emotional maturity, and this in connection with a slightly increased tendency to learning problems in school creates a need for early and adequate stimulation.

It is important that these boys at an early age attend a good day institution - kindergarten, and that there is a close co-operation between parents and the staff in the day institution -kindergarten. If the language development is delayed it is important to get a speech pedagogue for a while.

It is, however, a general condition that XYY boys develop quite normally during childhood.

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In a study of 60 XYY boys found among consecutively new-born children in USA, Canada, Scotland and Denmark intelligence was found to be normal with an average 10 of 105, both for the XYY boys and for the control group. In a study of 12 unselected Danish adult XYY males by Alice Theilgaard, there was no significant difference in intelligence compared with a control group.

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XYY boys usually manage within the normal range at school, but with a tendency to certain minor learning problems and school problems. In the above mentioned unselected group of XYY boys, school problems were found in approximately half in spite of a normal intelligence distribution. This can, however, be remedied by increased pedagogical efforts according to need including remedial teaching. Learning problems are most pronounced during the first years at school, and it is not found in nearly all XYY boys, but it is important to know that if such difficulties are present they need to be investigated and dealt with, both at home and at school. Such efforts usually give good results, and learning difficulties can be overcome. It is of great importance for both parents and teachers to know this and act accordingly. If there are problems in relation to speech development it is also important to give speech therapy.

If conditions at home are good, stable and stimulating, if the family accepts the relatively high level of physical activity in these boys, and if there have been good conditions in the day institution - kindergarten, where the XYY boy has been, learning problems are usually rare, and if they appear, they seldom have any consequences.

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Boys with XYY have no increased risk of diseases, nor is there any increased risk of diseases in adult life.

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Boys with XYY have an increased growth velocity during the earliest childhood, and the average final height for these males is approximately 7 cm above the expected final height. Body build is normal, and weight is comparatively low in relation to stature.

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The physical sexual development for XYY males is normal with normal development of sex organs and of secondary sex characteristics. Also puberty appears at the expected time.

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Sexual libido and potency is normal in XYY males.

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XYY males are fertile, they have testes of normal size, and they have a normal sexual libido and potency. In spite of a somewhat decreased sperm quality with many so-called immature sperm cells, the fertility seems to be normal. In the same way as for triple-X women, who as a rule do not get children with an extra X chromosome, males with XYY most probably only very rarely get sons with two Y chromosomes.

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A Danish investigation by Alice Theilgaard of 12 unselected XYY males compared with a control group showed that there was no difference with regard to frequency and time of marriage. Nor was there any difference between the XYY males and a control group with regard to the number of children, and the children of the XYY males were as healthy as those in the control group.

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No! XYY males have normal sex hormone conditions, contrary to males with Klinefelter's syndrome (47,XXY), who have decreased testosterone production. XYY males do not need treatment with sex hormones.

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Up till now there are no well documented studies concerning this except for the previously mentioned study by Alice Theilgaard of 12 unselected XYY males. She found no significant difference in work stability between the XYY males and the controls. Most investigations of adult XYY males comprise selected groups of these men. But available investigations indicate that XYY males are within the normal range with regard to occupation and work stability. Most of them are working in manual occupations, and there are relatively few with academic jobs. If XYY males grow up under good, stimulating and stable conditions they will usually be well adjusted as far as work is concerned and have an employment level as expected for their age group.

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No! XYY males should definitely not be considered as patients. With full information to the parents and themselves and with a good and stimulating environment, remedial teaching, help and support according to their need during childhood, in school and in general they will usually manage quite well or at least within the normal range.

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For XYY boys who grow up in a good environment with the love, support and stimulation they need as well as help at school if they have needed it, there will be no increased risk of mental illness.

For XYY males who grow up in a poor environment without sufficient stimulation, help, love and support there is a slightly increased risk of having social and mental problems as well as problems in social adjustment compared with siblings. Such XYY males can, however, be helped with psychological-psychiatric counselling and treatment, and there is no increased risk of schizophrenia, manic-depressive disorders or any other serious mental illness.

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Yes! Parents of XYY boys should always have full information. It is very important that parents get as much knowledge as possible about XYY as early as possible in the life of their son and preferably already from birth. This is important for many reasons, but especially because it makes it possible for them to create the best possible conditions for their XYY son with support in kindergarten and school if needed, good conditions in childhood in general and canalising a high level of activity into sports activity, creative and physical activities as well as a good accept of having a child with a high level of physical activity.

There are many examples of parents, who first relatively late got the information that their son had XYY, realising that they could have done much more for him at an earlier period in life, if they had got the information about what XYY is and what can be done for XYY boys.

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As it is the case concerning information to the parents, the answer according to our experience in Risskov is definitely yes. It is clearly wrong to try to protect the XYY boy by avoiding to explain to him what XYY is. He will try to find out himself anyway, and being secretive about it can only lead to anxiety and lack of confidence in parents, physicians and adults in general.

It is our experience that XYY males in the same way as persons with other sex chromosome aberrations often have been poorly informed and informed too late. They have often made their own impression and imagination about what is wrong, and this is usually worse than getting the real information. Information about XYY should be given by persons with a good knowledge and experience concerning XYY in boys as well as adult males and persons with plenty of time. I also think that such information should be given by members of XYY contact groups, if such groups are available, and if the male in question is interested in talking with members of an XYY contact group.

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Twenty of 28 foetuses (71%) with XYY diagnosed by prenatal chromosome examination in Denmark from 1970 to 1987 were aborted. On the background of better and more realistic information during recent years about the development of XYY boys and more information in general there has been a considerable fall in the frequency of induced abortions of XYY foetuses from 100% from 1970 to 1980 to 57% from 1985 to 1987. This is no doubt due to the information from the Cytogenetic Laboratory, Risskov, follow-up of approximately 60 unselected XYY boys diagnosed at birth in special investigations in Denmark, USA, Canada and Scotland as well as a good investigation of a small group of unselected adult males with XYY in Copenhagen.

Parents make their own decision whether to carry through the pregnancy in case of an XYY foetus or have it interrupted with induced abortion, but they make it on the background of the information they are given by the counsellors and the weight they have put on the positive contra the negative aspects of XYY and to some degree on the background of the counsellor's attitude to abortion of an XYY foetus.

It is very important that prenatal counsellors stress the information that XYY boys have a normal intelligence and that they generally develop within the normal range in all areas if as previously described they have grown up in a good, stimulating, stable and loving environment where they get the support and help they need.

To hint at or to have the attitude that XYY foetuses should be aborted is in my opinion a clear discrimination against XYY males who usually are healthy physically and mentally and with an intelligence within the normal range.

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Information to the public about XYY males should be given by professionals with a good knowledge of XYY. Information should be given in close co-operation with XYY contact groups where such groups are found. We physicians have got and still get a rather poor education with regard to giving full information to the public about disorders and deviations in general. It is my experience that the value of a good understanding of any chromosome aberration and easily available information cannot be overestimated, and this is also the case of XYY.

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In the same way as there now are Turner contact groups in many countries: Canada, USA, Australia, Denmark, Great Britain, Germany, Spain, France, Switzerland and national societies of Turner contact groups in Canada, USA, Denmark and other countries, there should definitely also be XYY contact groups. In this connection it might be mentioned that we have recently established a Klinefelter's/triple-X contact group in Århus, and I hope that this group within the near future will be extended to comprise also XYY boys, their parents and adult XYY males.

The Klinefelter/triple-X contact group has so far met four times, and the group has published a folder with the following text: "The background for the establishment of a contact group for people/families with Klinefelter and triple-X is that Johannes Nielsen in 1988 invited to a meeting where some Klinefelter and triple-X families met for the first time. We found it exiting and informative to discuss thoughts and problems we had in common, and as a natural consequence of this meeting we made a contact group which will meet approximately every second month.

We feel that there is a need for contact groups for several reasons. Most important is our need of talking with and having contact with families with a child with the same chromosome aberration.

It is our wish to contribute with better information to coming parents of children with either Klinefelter or triple-X, and later on also to encourage and support ongoing research and if possible improve this. If there should be a need for a national association of Klinefelter/triple-X contact groups, we will of course discuss this.

The intention with the contact group meetings on the short run is to have a cosy time together, where adults and children get to know each other, exchange experiences and support each other. We will most probably also invite persons who can contribute with some further information, both specialists and adult Klinefelter and triple-X individuals. Further information: Bente Nielsen, Tel. 86 - 29 29 61 (representing triple-X families), and Hakon Wellnitz, Tel. 86 - 17 47 63 (Klinefelter families)."

Concerning information about XYY males as well as about the Klinefelter/triple-X contact group you may call Johannes Nielsen, Cytogenetic Laboratory, Århus Psychiatric Hospital, DK-8240 Risskov, Tel. 86 - 17 77 77, ext. 549.

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Literature

Netley, CT. (1986): Summary overview of behavioural development in individuals with neonatally identified X and Y aneuploidy. In: Prospective studies on children with sex chromosome aneuploidy (S.G. Ratcliffe & N. Paul, eds.). Birth Defects: Original Article Series 22. Alan R. Liss, Inc., New York, pp.293-306.

Nielsen, J., I. Sillesen, A.M. Sørensen & K. Sørensen (1979): Follow-up until age 4 to 8 of 25 unselected children with sex chromosome abnormalities, compared with sibs and controls. In: Sex chromosome aneuploidy: Prospective studies on children (A. Robinson, H.A. Lubs & D. Bergsma, eds.). Birth Defects: Original Article Series 15. Alan R. Liss Inc., New York, pp.15-73.

Nielsen, J. (1979): Fejludvikling af kromosomerne. En orientering. Arkona, Århus, 1979.

Nielsen, J., AM. Sørensen & K. Sørensen (1982): Follow-up until age 7 to 11 of 25 unselected children with sex chromosome abnormalities. In: Children with sex chromosome aneuploidy: Follow-up studies (D.A. Stewart, ed.). Birth Defects: Original Article Series 18. Alan R. Liss, Inc., New York, pp.61-97.

Nielsen, J. (1984): Information, rådgivning og hjælp. I: Børn - Ja! Men hvilke? (N. Carstensen, RK. Graugaard, V.E. Knudsen, B. Windelborg & J.H. Østergaard, eds.). FADL'S Forlag, København, pp.154-163.

Nielsen, J., M. Wohlert, J. Faaborg-Andersen, G. Eriksen, K.B. Hansen, L. Hvidman, B. Krag-Olsen, I. Moulvad & P. Videbech (1986): Chromosome examination of 20,222 new-born children: Results from a 7.5-year study in Århus, Denmark. In: Prospective studies on children with sex chromosome aneuploidy (S.G. Ratchife & N. Paul, eds.). Birth Defects: Original Article Series 22. Alan R. Liss, Inc., New York, pp.209-219.

Nielsen, J. (1986): The importance of early diagnosis of children with sex chromosome abnormalities. In: "From Man to Gene. From Gene to Man". Proceedings of the International Symposium, Florence, Italy, pp.204-216.

Ratcliffe, S.G. & N. Paul (1986): Prospective studies on children with sex chromosome aneuploidy. Birth Defects: Original Article Series 22. Alan R. Liss, Inc., New York. Robinson, A., HA., Lubs & D. Bergsma (1979): Sex chromosome aneuploidy: Prospective studies on children. Birth Defects: Original Article Series XV. Alan R. Liss, Inc., New York.

Stewart, D.A. (1982); Children with sex chromosome aneuploidy: Follow-up studies. Birth Defects: Original Article Series 18. Alan R. Liss, Inc., New York.

Theilgaard, A. (1984): A psychological study of the personalities of XYY- and XXY men. Acta Psychiatrica Scandinavica (suppl.) 69, No.315, p.133.