We have examined the complete longitudinal height velocity (HV) data of 135 (80 male and 55 female) chromosomally normal children from the Edinburgh Longitudinal Growth Study who were measured six-monthly between age 3 years and the onset of the adolescent growth spurt. Individual HV curves appeared to consist of a regular series of accelerations and decelerations in a cyclical fashion. After excluding variations due to measurement error, and basing the analysis on the pattern of acceleration, we were able to identify a number of spurts of regular occurrence. The mid-childhood spurt was clearly identified at ages 7.0 in boys and 6.7 years in girls, and could be identified in all children except one girl. Other spurts were also apparent; a pre-school spurt at ages 4.8 and 4.6, a late-childhood spurt at ages 9.2 and 8.6, and in children with an average-to-late onset of puberty, a prepubertal spurt at ages 10.8 and 10.0 years in boys and girls respectively. Synchronization at peak HV was performed for each spurt as described by Shuttleworth (1937) for the adolescent growth spurt. The overall pattern of growth appeared to be cyclical with a mean peak interval of 2.2 years in boys and 2.1 years in girls, the cycles appearing to continue until interrupted by the onset of the adolescent growth spurt. Sitting height velocity (SHV) and leg length velocity (LLV) curves also showed a cyclical pattern, but each varied independently. The magnitude of the HV spurts in an individual was dependent on the synchrony between the phases of SHV and LLV spurts. The cyclical pattern of prepubertal growth with its rapid changes in HV should be taken into account when assessing the growth of any child and in the response to any treatment offered.
SUMMARY At all ages XXX girls had significantly smaller head circumferences than control girls. Their IQ deficit was 24 points and IQ at age seven correlated significantly with head circumference at birth. In XXY boys, head circumference was significantly reduced at birth and up to nine years of age. The XXY boys' IQ deficit was 22 points, but IQ did not correlate with head circumference, as reductions in the two parameters did not always occur in tandem. The ratio of height‐to‐head circumference differed most in this group and could be useful in clinical recognition of this condition. XYY boys' head size did not differ from controls, despite their greater height, lower IQ scores indicating an adverse effect of an additional Y chromosome on brain development. The major factor affecting IQ outcome in the cohort was abnormal karyotype, with smaller effects from social class and head growth. RÉSUMÉ Tour de tête et QI d'enfanis présentant des anomalies des chromosomes sexuels A tout âge, les filles XXX avaient un tour de tête significativement inférieur à celui de filles contrôles. Leur déficit en QI était de 24 points et le QI à l'âge de sept ans était significativement corrélé au tour de tête à la naissance. Chez les garçons XXY, le tour de tête était significativement diminuèà la naissance et jusqu'à l'âge de neuf ans. Le deficit en QI des garçons était de 22 points mais il n'y avait pas de correlation avec le tour de tête, la diminution dans les deux paramètres n'allant pas toujours de pake. Le rapport taille/tour de tête était particulièrement différent dans ce groupe et pourrait constituer un indicateur clinique de l'anomalie. Le tour de tête des garçons XYY ne différait pas des contrôles en depit d'une plus grande taille, de scores de QI plus bas traduisant l'effet négaitif d'un chromosome Y additionnel sur le développement du cerveau. Le facteur majeur déterminant le devenir du QI dans le groupe étudiéétait le caryotype anormal, avec des effets plus reduits de la classe sociale et de la croissance céphalique. ZUSAMMENFASSUNG Kopfumfang und IQ bei Kindern mil Geschlechtschromosomenaberrationen XXX Mädchen hatten in alien Altersgruppen einen signifikant kleineren Kopfumfang als Kontrollmädchen. Ihr IQ‐Defizit betrug 24 Punkte und ihr IQ im Alter von sieben Jahren korrelierte signifikant mit dem Kopfumfang bei Geburt. Bei XXY Jungen war der Kopfumfang bei Geburt und bis zum neunten Lebensjahr signifikant kleiner. Das IQ‐Defizit der Jungen betrug 22 Punkte, aber es fand sich keine Korrelation zwischen IQ und Kopfumfang, da die Verminderungen bei den beiden Parametern nichi immer gleichzeitig auftraten. Die Relation Größ/Kopfumfang unterschied sich in dieser Gruppe am meisten und könnte zur klinischen Diagnose dieser Erkrankung herangezogen werden. Der Kopfumfang von XYY Jungen unterschied sich nicht von dem der Kontrollen, obwohl sie größer waren, die niedrigeren IQ Scores wiesen auf einen schädigenden Einfluß eines überzähligen Y Chromosoms hin. Der Hauptfaktor für die IQ Entwicklung in dieser Gruppe war der abn...
The availability of a cohort of eight unselected XYY boys identified by newborn cytogenetic screening has enabled their growth to be studied longitudinally in comparison with controls from the same population. While no difference had been found in dimensions at birth, increased height velocity in childhood resulted in the XYY boys being 7.6 cm taller at the onset of their pubertal growth spurt. Increased intensity of growth at puberty with a peak height velocity of 10.6 cm/year contributed to their adult height of 188.1 cm. XYY boys showed twice the male-female difference in height implying that genes on the Y chromosome exert a quantitative effect on the sexual dimorphism of growth.
Longitudinal measurements of height, sitting height and leg length are compared between 11 XXX girls identified by cytogenetic screening, and 16 chromosomally normal controls from the same population using a nonparametric method. While height velocity did not differ between the two groups either during the pubertal or the mid-childhood spurts, leg length velocity was significantly increased during the mid-childhood spurt, between 4 and 9 years of age. A further contribution to the increased leg length came from the slower decline in leg length velocity at the end of the pubertal spurt. The possible mechanisms involved in these changes are discussed.
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