See Also: Powassan encephalitis(medicine)
Powassan virus(medicine)
Herbal medicine (botanical medicine, herbology, phytomedicine)(health)
Klinefelter(medicine)
Klinefelter(dictionary)
Klinefelter's Syndrome(health)
Klinefelter syndrome(encyclopedia)
klinefelter syndrome(medicine)
Klinefelter's syndrome(medicine)
syndrome, klinefelter(medicine)

klinefelter syndrome (medicine) and Powassan encephalitis (medicine)


klinefelter syndrome (medicine)


Klinefelter syndrome
<syndrome> A genetic syndrome observed in many mammals caused by the presence of an extra X chromosome in the male karyotype.

The normal male is XY but in this disorder the chromosomal abnormality is XXY, and affects only males. Infertility is common. In humans, the infant appears normal at birth, but the defect usually becomes apparent in puberty when secondary sex characteristics fail to develop along with female escutcheon, gynaecomastia, tall stature, small testes, aspermatogonia and Leydig cell hyperplasia.

It is characterised by small testes, feminine appearance, sterility (except in the case of genetic mosaics) and there is no effect on performance IQ but the verbal IQ can be affected.

The genetic abnormality can be detected in 0.003% of spontaneous abortions and is associated with nondisjunction in paternal meiosis I (53%), maternal meiosis I (34%) and maternal meiosis II (9%). In a large number of patients the karyotype shows a 47,XXY constitution and in 10% of the cases there is mosaicism and some of these mosaics can be fertile. Patients with mosaic karyotypes that include 48,XXXY and 49,XXXXY can show short stature, mental retardation, hypogonadism and Other abnormalities.

Incidence: 1 in 1000 to 1 in 2000 newborn males.


Powassan encephalitis (medicine)


Powassan encephalitis
<neurology, paediatrics> An acute disease of children varying clinically from undifferentiated febrile illness to encephalitis.

It is caused by the Powassan virus, a member of the Flaviviridae family, and transmitted by ixodid ticks; most frequently seen in Canada.