Clinical and cytogenetic aspects of X‐chromosome deletions

Abstract

Karyotype/phenotype correlations in six non‐mosaic patients with dysgenetic ovaries and partial deletions of the X‐chromosome (three patients with short arm, and three with long arm deletions) are presented and the pertinent literature is analysed. It would appear that functioning ovarian tissue is present more often in patients with a short arm deletion than in those with a deleted long arm. This may represent a difference in the strength of two sets of controlling factors, but it can also be related to break point position. This in turn may be misinterpreted due to the difficulty in distinguishing between terminal and interstitial deletions in the long arm. Stature may be a heterochromatic effect, but if specific genetic factors influencing stature exist, then they would appear to be situated mostly on the short arm of the X‐chromosome, although some ‘statural determinants’ occur also on the long arm and could be located rather close to the centromere. Deletions of the short arm of the X‐chromosome were almost always associated with some features of the Turner phenotype, and could possibly be related to a gene dosage effect.

Cytogenetic evaluation of patients with clinical spectrum of Turner syndrome

“…Deletion involving the long arm of X chromosome generally results in ovarian failure if they involve the proposed critical region Xq13-q26. [17] In our study, it was evidenced that eight subjects had X chromosome structural abnormalities of partial monsomy/trisomy 46,X,del (Xp), 46,X, del(X)q, 46,X ring(X), and 46,X,iso(X) as shown in Figure 1a–h.…”

Chromosomal mosaicism mitigates stigmata and cardiovascular risk factors in Turner syndrome

“…Central obesity might contribute to the increased metabolic risk 10–12 . Correlations between different karyotypes and phenotypic characters have been demonstrated, but knowledge regarding genotype and phenotype correlations in TS is poor, especially in those with mosaicism 13–19 . In those older studies, however, only a few cells were used in the karyotyping process.…”

The frequency of occurrence of abnormal frenal attachment of lips and enamel defects in Turner syndrome

“…Many attempts have been made to correlate the type of X chromosome anomaly such as totally missing chromosome X (45X), aberrations of chromosome X (partial deletions of short and long arms, isochromosomes) and various mosaicisms in group of Turner syndrome individuals with their clinical features (Kusiak et al , 2000, 2005). The classical abnormalities of Turner syndrome include many somatic anomalies, such as short stature, infantile external genitalia, webbed neck, cubitus valgus, low hairline, shield‐like chest, anomalies in the structure of some internal organs and others (Turner, 1938; Horowitz and Morishima, 1974; Palmer and Reichmann, 1976; Arulanantham et al , 1980; Jaspers and Witkop, 1980; Goldman et al , 1982; Hall and Gilchrist, 1990; Lippe, 1991; Pelz et al , 1991; Temtamy et al , 1992; Robinson and de la Chapelle, 1996; Lopez et al , 2002). Some oral abnormalities were also observed, such as malocclusion (Harju et al , 1989; Laine et al , 1992; Szilagyi et al , 2000), early development of permanent teeth (Filipsson et al , 1965), high‐arched palate (Horowitz and Morishima, 1974), small teeth (Townsend et al , 1984; Varrela et al , 1988; Mayhall et al , 1991; Mayhall and Alvesalo, 1992; Midtbo and Halse, 1994a,b; Townsend and Alvesalo, 1995; Kusiak et al , 2000; Szilagyi et al , 2000; Zilberman et al , 2000), crown hypoplasia (Lopez et al , 2002), abnormalities in intercuspal distance (Lopez et al , 2002) and abnormality of root morphology of mandibule were also observed (Varrela, 1990, 1992; Lopez et al , 2002; Kusiak et al , 2005).…”