Mosaic Down's syndrome with de novo 45,XX,-21,-22,+t(21q;22q)/46,XX,-21,+t(21q;21q) rearrangement.

The occurrence of mosaic Down's syndrome with two independent Robertsonian translocation cell lines is very rare. Such a patient is reported here, in whom an unbalanced Robertsonian translocation between two chromosomes 21 was detected in the majority of cells. The patient also revealed a minor cell line with a second Robertsonian translocation involving a chromosome 21 and a 22. The chromosome translocations detected in this patient were de novo in origin.

Lecithin: cholesterol acyltransferase in Down's syndrome.

Based on earlier reports indicating that Down's syndrome may represent an atheroma-free human model, two groups of institutionalized subjects were compared with respect to various parameters of their plasma lipid transport system. One group of subjects was comprised of Down's syndrome subjects and the second, a group of mentally retarded individuals. Parameters measured included plasma cholesterol, triglyceride, HDL-cholesterol, apolipoprotein levels (A-I, B, C-III, and E), lecithin:cholesterol acyltransferase (LCAT) activity, body mass and blood pressure. Statistical analyses indicated no significant differences between the two groups except for the lower fractional rate of cholesterol esterification (% cholesterol esterified per hour, p = 0.0049) in the Down's syndrome subjects. Adjustment for the effects of body mass and age revealed no other significant differences between the two groups except for a lower molar rate of esterification (nmol cholesterol esterified X h-1 X ml-1, p less than 0.0063) in the Down's syndrome subjects. Additional differences between the two groups were revealed by partial correlational analyses of LCAT activity with the measured parameters or ratios of these parameters which suggests that the composition and/or metabolism of lipoproteins may differ between these two groups. Whether the lower LCAT activity and the other differences reflected by the correlational analyses contribute to the decreased incidence of atherosclerotic lesions in Down's syndrome remains to be elucidated.

Offspring of teenage mothers: congenital malformations, low birth weights and other findings.

Teenage mothers were found to have congenitally malformed infants with a significantly higher frequency when compared to a published control population. Low birth weight and perinatal death were common among the infants of mothers 17 and younger. No chromosomal anomalies were found among the infants of this population, but this result does not unequivocally rule out an increased frequency of these disorders.

Long survival in trisomy-13-syndrome: 21 cases including prolonged survival in two patients 11 and 19 years old.

The mean survival in Trisomy-13-syndrome patients is reported to be 130 days. We have diagnosed 21 cases of this syndrome in this institution (11 females and 10 males); 15 patients had regular trisomy 13 and 6 had translocation-trisomy 13 karyotypes. The mean survival of the 19 patients who died was 97.05 days; translocation patients survived longer than regular trisomy patients. The oldest living patients with trisomy 13 are a girl 19 and a boy 11 years old. Both are black, have regular trisomy 13 karyotypes and have had most of the manifestations of the syndrome. No mosaicism was detected in repeated cytogenetic studies. The 19-year-old patient is the oldest known living person with regular trisomy 13.

A simple method for the intravenous fat-tolerance test.

A simple method for measuring intravenous fat tolerance with an artificial fat emulsion (intralipid) was studied and compared with the currently used method of Carlson and Rossner [J. Lab. Invest. 29, 271-280 (1972)]. The proposed method uses as little as 3 mL of whole blood to follow, by nephelometry, the elimination of intravenously administered fat emulsions. There is a high correlation between the K2 values obtained by the current method for plasma and those obtained by the proposed method (r = 0.903). The latter is simpler, quicker, and more acceptable to patients.

Cholinesterase in serum and low density lipoprotein of hyperlipidemic patients.

Cholinesterase activity in the low density lipoprotein fraction of serum is increased in types IIa, IIb and IV hyperlipoproteinemic patients, whereas only types IIb and IV show increases in serum cholinesterase activity. In obese patients, cholinesterase activity is increased both in the serum and low density lipoprotein fraction only when hyperlipidemia is present. Cholinesterase activity is also found to increase in proportion with increases in low density lipoprotein, cholesterol, and triglycerides both in the serum and low density lipoprotein fraction. We suggest on the basis of these findings that cholinesterase has a function in lipid and lipoprotein metabolism.

Serum cholinesterase: function in lipoprotein metabolism.

Human serum beta-lipoproteins, isolated by percipitation with heparin-calcium mixture, showed cholinesterase activity. The enzyme activity was almost proportional to the lipoprotein concentration. Rats, treated with neostigmine, a cholinesterase inhibitor, showed a significant decrease in serum beta-lipoprotein and in the incorporation of H3-lysine into the lipoprotein compared to untreated controls. The decreased incorporation of H3-lysine into beta-lipoprotein was associated with increased labelling of alpha-lopoprotein. There was no significant difference in the labelling of pre-beta-lipoprotein. We propose that LDL is formed from VLDL in the presence of cholinesterase.