12. GENETIC CYTOLOGY
407
syndrome, like the Klinefelter's, constitutes another reverse of the
"orthodox". In the mouse, however, X O genotype results in a fertile
female (Welshons and Russell, 1959).
In a female patient who displayed some symptoms of Turner's
syndrome (primary amenorrhea, faulty development of secondary sex
characters, hypoplastic uterus, no ovaries except some connective
tissue which upon histological examination revealed some ovarian
tissue and rudimentary follicles), few somatic nuclei possessed sex
chromatin ( 7 % instead of the 5 0 % or more in normal females).
Jacobs, Harnden, Court Brown, Goldstein, Close, MacGregor, Maclean
and Strong (1960) found that the cells contained 46 chromosomes.
However, the idiogram of this individual showed that one chromosome
was abnormal. Among the group C chromosomes, only 15 were found
(normally 16 for females). This strongly suggests that only one X was
present. The abnormal chromosome was an acrocentric element having
its long arm similar in length to that of the X . Jacobs et al. interpreted
from cytological and morphological data that the abnormal element was
the X with most of the short arm deleted. A more extensive analysis
has recently been presented by Jacobs, Harnden, Buckton, Court
Brown, King, McBride, MacGregor and Maclean (1961) on the variations of the X O genotype, which include the loss of a short arm,
possible isochromosome of the long arm of the X , etc. Mosaicism with
X X / X O , X O / X Y , X O / X Y Y genotypes (de Grouchy, Lamy, Frezal
and Ribier, 1961; Lindsten, 1961), as in Klinefelter's syndrome, also
appears common.
C. THE X X X GENOTYPE
The first case of human female believed to be of X X X condition was
reported by Jacobs, Baikie, Court Brown, MacGregor, Maclean and
Harnden (1959c). The nuclei possessed 2 sex chromatin bodies each.
Later, several more cases of similar nature were found (Jacobs et al.,
1960; Stewart and Sanderson, 1960; Fraser, Campbell, MacGillivray,
Boyd and Lennox, 1960; Barr and Carr, 1960). As a group, the X X X
genotype does not form a well-defined syndrome. The first patient
analyzed by Jacobs et al. had amenorrhea, but other individuals did
not have this defect. In fact, some had children. Most of the known
cases have some mental retardation, but it is still not established that
there is an absolute relationship.
Variations of the X X X group include the X X X X genotype (Barr
and Carr, 1960) and mosaics (Jacobs et al., 1960). In Drosophila, X X X
genotype is known as "superfemale". Jacobs et al. (1959c) borrowed this
term when reporting their first human case. It was objected to by Stern
407
syndrome, like the Klinefelter's, constitutes another reverse of the
"orthodox". In the mouse, however, X O genotype results in a fertile
female (Welshons and Russell, 1959).
In a female patient who displayed some symptoms of Turner's
syndrome (primary amenorrhea, faulty development of secondary sex
characters, hypoplastic uterus, no ovaries except some connective
tissue which upon histological examination revealed some ovarian
tissue and rudimentary follicles), few somatic nuclei possessed sex
chromatin ( 7 % instead of the 5 0 % or more in normal females).
Jacobs, Harnden, Court Brown, Goldstein, Close, MacGregor, Maclean
and Strong (1960) found that the cells contained 46 chromosomes.
However, the idiogram of this individual showed that one chromosome
was abnormal. Among the group C chromosomes, only 15 were found
(normally 16 for females). This strongly suggests that only one X was
present. The abnormal chromosome was an acrocentric element having
its long arm similar in length to that of the X . Jacobs et al. interpreted
from cytological and morphological data that the abnormal element was
the X with most of the short arm deleted. A more extensive analysis
has recently been presented by Jacobs, Harnden, Buckton, Court
Brown, King, McBride, MacGregor and Maclean (1961) on the variations of the X O genotype, which include the loss of a short arm,
possible isochromosome of the long arm of the X , etc. Mosaicism with
X X / X O , X O / X Y , X O / X Y Y genotypes (de Grouchy, Lamy, Frezal
and Ribier, 1961; Lindsten, 1961), as in Klinefelter's syndrome, also
appears common.
C. THE X X X GENOTYPE
The first case of human female believed to be of X X X condition was
reported by Jacobs, Baikie, Court Brown, MacGregor, Maclean and
Harnden (1959c). The nuclei possessed 2 sex chromatin bodies each.
Later, several more cases of similar nature were found (Jacobs et al.,
1960; Stewart and Sanderson, 1960; Fraser, Campbell, MacGillivray,
Boyd and Lennox, 1960; Barr and Carr, 1960). As a group, the X X X
genotype does not form a well-defined syndrome. The first patient
analyzed by Jacobs et al. had amenorrhea, but other individuals did
not have this defect. In fact, some had children. Most of the known
cases have some mental retardation, but it is still not established that
there is an absolute relationship.
Variations of the X X X group include the X X X X genotype (Barr
and Carr, 1960) and mosaics (Jacobs et al., 1960). In Drosophila, X X X
genotype is known as "superfemale". Jacobs et al. (1959c) borrowed this
term when reporting their first human case. It was objected to by Stern