Enlarged Short Arm or Satellite Region – A Heritable Trait Probably Unassociated with Developmental Disorder

Abstract

In the family described here, the grandmother, father, and 3 of his 9 children had an apparently abnormal chromosome of group 21–22. The abnormality was similar in morphology in all the affected subjects and was found in metaphases from cultures of leukocytes, and skin and bone marrow. The short arm of the abnormal chromosome seemed longer than normal; it was not possible to ascertain whether the satellite itself or the short arm, or both, were enlarged. Of the 5 subjects affected, 4 were clinically normal. The fifth, a girl, had severe abnormalities of the central nervous system. One of her brothers, who was cytogenetically normal, had a similar syndrome of unknown origin. From these data, and from those published by others, it was postulated that an apparently enlarged satellite region is compatible with normal development. Such an abnormality does not necessarily imply an association with developmental disorder in the offspring of carrier subjects.

Cytogenetic Study of Seventy‐three Patients With Down's Syndrome

“…"Large satellites of the short arms of an acrocentric chromosome" is a more difficult phenomenon to define exactly. It has been dealt with before in this laboratory (de la Chapelle, Aula and Kivalo, 1963). Our criteria for these minor deviations of the karyotype seem to be similar to those of Court Brown, Jacobs and Brunton (1965).…”

Split and enlarged satellites in man

“…They are also found in normal Chapelle, 1963). The present investigation shows that it may also occur sporadically due to unknown causes under apparently well controlled culture conditions.…”

Cytogenetic and Functional Studies of Leukocytes with Pelger-Huët Anomaly

“…However, familiar occurrence of the enlarged chromosome was frequently observed. Indeed, the frequencies of 22p+ in the general population were 0.5% in Scotland [2] and 2.1% in Tokyo [37], In general, the enlarged short arm of a G group (Gp+) is interpreted as heteromor phism of the chromosome and does not imply an association with clinical disor ders [3,22], We should also like to suggest that the association of 22p+ and P-H anomaly in the present may well be fortui tous, and that P-H anomaly was uncon nected with chromosomal aberration.…”