Validation of automated sleep analysis in normal children.

With the aim of determining normal reference values for our sleep laboratory and evaluating the reliability of automated analysis for scoring polysomnographic studies in children, we recorded polysomnograms in 16 healthy boarding-school children. Sleep recordings were obtained with a computer system (Medilog SAC, Oxford Instruments). Polysomnographic variables were monitored continuously on a 16-channel recorder equipped with a video. Data were acquired on optical disk for computer-assisted data interpretation. Sleep stages and respiratory events were also scored visually by operator. Comparison with visual scores showed that the computer system significantly overscored wakefulness (W) (p<0.02) and stage IV (p<0.001) and underscored stage II (p<0.001) and rapid eye movement (REM) sleep (p<0.001). It also assigned respiratory events a higher score than did visual scoring, as shown by the higher apnoea index (AI) and hypopnoea index (HI) (AI p<0.03; HI p<0.001). Regression analysis showed a significant correlation between visual and automated scores for central (r=0.679; p<0.004) and obstructive apnoea (r=0.631; p<0.008). Computer apnoea scores did not correlate with visual scores. Much remains to be done before computer-based scoring systems can be relied upon, without visual scoring, for polysomnographic sleep studies in children. Their main advantage at present is that they offer a convenient means of saving paper, space and time.

The frequency of chromosomal abnormalities in patients referred for fragile X analysis.

The present paper summarizes our existing database on chromosomal abnormalities found in patients referred because of a question of the Fragile X Syndrome during the period from January 1, 1990 to June 30, 1995. Cytogenetic results were derived from testing performed at the cytogenetics laboratory at Rhode Island Hospital. All positive fragile X individuals detected among our sample population represent index patients from separate kindreds. Of a total of 327 cases referred for fragile X testing, 10 (3.06 percent) were found to be positive for fragile X by either cytogenetics alone or by both cytogenetics and DNA testing, 12 (3.60 percent) were found to be positive for either a numerical or structural chromosomal abnormality, while 10 (3.06 percent) were found to exhibit a heteromorphism. Positive chromosomal findings included numerical chromosomal abnormalities of the sex chromosomes and autosomes, deletions, and translocations. Heteromorphism mostly involved an increase in the length of heterochromatic regions of certain chromosomes as well as a pericentric inversion of a chromosome 9, usually considered normal variants. It is concluded that chromosomal abnormalities other than fragile X are found with equal and, in some cases, higher frequency than the frequency of fragile X positivity in patients referred for a question of the Fragile X Syndrome. Our figures, consistent with those reported in the literature, underscore the value of routine karyotyping in this population of patients. Except under special circumstances, it is important that GTG-banding analysis be performed so that the entire human genome be examined in addition to scoring for the fragile X mutation on Xq27.3. Especially in view of the recent finding of the relative rarity of this condition, the exclusive use of DNA analysis is not advised.

Menstrual cycles and basal body temperature curves in women with Down syndrome.

Menstrual histories were obtained from 51 females with Down syndrome between the ages of 10-27 years. The average age at onset of menstruation of girls in our study was 12 years, 6 months. Seventy-six percent of them had regular menstrual cycles with an average length of menstrual flow of 4 days, and most menstrual cycles lasted 25-30 days. Eight of the women with regular menstrual cycles provided 26 basal body temperature charts. When basal body temperatures were graphed using the smoothed-curve technique, 88.5% had biphasic curves indicative of an ovulatory pattern.

Parents' perception of social and sexual functions in adolescents with Down's syndrome.

The authors investigated parental perceptions of social interactions, interest in the opposite sex, sexual functions and issues concerning sex education in young persons with Down's syndrome. The evaluation of the data revealed that more than half of the study population showed interest in the opposite sex and are attending social gatherings. Many of the youngsters had expressed a desire to get married, however, only a few had an interest in sexual relationships. Masturbation was observed in 40% of the young men and in 22% of the young women. About half of the parents feel that their children should be sterilized or should have other forms of birth control if they would be able to reproduce. Only a limited number of adolescents had sex education. More parents who have girls with Down's syndrome than those who have boys are worried that their child may be taken advantage of sexually.

Partial trisomy 2p.

A 4-year-and-10-month-old girl was referred to the Child Development Center, Rhode Island Hospital, Providence, Rhode Island, USA, for evaluation because of mental retardation. She was found to have short stature, congenital heart disease and dysmorphic facial features. A chromosome analysis revealed an unbalanced translocation with trisomy of the distal part of the short arm of chromosome 2 (2p21----2pter). A balanced reciprocal translocation was identified in the maternal karyotype 46,X,t(X;2)(q28;p21). The phenotype of partial trisomy 2p is discussed.