Gonosomal aneuploidy syndromes in man

Aneuploidy – change in chromosome number by less than a complete set, 			usually ± 1 chromosome

Trisomy – three copies of sex chromosomes

Monosomy – one copy of chromosome; monosomy of chromosome X is only monosomy viable in man

Turner syndrome
gonadal dysgenesis (rudimentary fibrous ovaries), primary amenorrhoea, average intelligence (not retarded), but frequently learning difficulties
 * monosomy of chromosome X; karyotype 45,X
 * Frequency 1:2 000-2 500
 * Phenotype (female):
 * short stature, broad/shield chest, underdeveloped breast, hygroma colli cysticum (usually detected by ultrasound prenatally), short webbed neck (pterygium colli), palms and feet oedemas (newborns), low posterior hairline
 * Therapy: hormonal therapy – growth hormone (height) and sex hormones (sexual features); in vitro fertlilization with oocyte donor
 * Life expectancy: usually not limited (more than 90 % of fetuses do not survive, monosomy X is most frequent finding in spontaneous abortions

Klinefelter syndrome

 * karyotype 47,XXY
 * Frequency 1:500-1 000
 * Phenotype (male):
 * tall stature, sterility – azoospermia, testicular atrophy, cryptorchism, female pubic hair pattern, poor beard growth, female type of fat distribution, gynaecomastia, average intelligence (not retarded), male psychosexual orientation

XXX syndrome („superfemale“)

 * trisomy X; karyotype 47,XXX
 * Frequency 1:1 000
 * Phenotype:
 * no specific phenotype, average intelligence, normal sexual development, decreased fertility (spontaneous abortions), without higher risk of chromosomal aberrations in offspring, no increased occurrence of congenital disorders

XYY syndrome („supermale“)

 * karyotype 47,XYY
 * Frequency 1:1 000
 * Phenotype:
 * „robust“ growth (proportional), especially height, average intelligence, normal sexual development, normal fertility, without higher risk of chromosomal aberrations in offspring, controversial hypothesis - affected psychosocial development