Effect of type of early infant feeding on fatty acid composition of plasma lipid classes in full-term infants during the second 6 months of life

BACKGROUND

Previously, the authors found significantly higher arachidonic and docosahexaenoic acid values in plasma lipids in 2-month-old full-term infants fed human milk than in those receiving formula. This is the report of data obtained in full-term infants during the second half of the first year of life.

METHODS

Healthy, full-term infants fed human milk (n = 12) or formula without preformed long-chain polyunsaturated fatty acids (n = 12) were investigated. Fatty acid composition of plasma lipid classes was determined by high-resolution capillary gas-liquid chromatography.

RESULTS

Linoleic acid acid values in plasma phospholipids (18.5 [3.94] vs. 20.79 [4.34]) and gamma-linolenic acid values in plasma cholesteryl esters (0.17 [0.09] vs. 0.27 [0.20]) and triacylglycerols (0.27 [0.18] vs. 0.46 [0.27]) were significantly (P < 0.05) lower in breast-fed infants than in those receiving formula. Data are percentage weight by weight shown as median (range from 1st to 3rd quartile) for breast-fed vs. formula fed infants, respectively. In contrast, arachidonic acid values in plasma phospholipids (10.05 [2.90] vs. 7.03 [1.87]; P < 0.01), cholesteryl esters (7.54 [3.58] vs. 4.09 [1.81]; P < 0.05), and triacylglycerols (1.28 [0.84] vs. 0.80 [0.39]; P < 0.05), as well as docosahexaenoic acid values in plasma phospholipids (1.92 [0.36] vs. 1.02 [0.31]; P < 0.001), cholesteryl esters (0.39 [0.13] vs. 0.15 [0.13]; P < 0.001), and triacylglycerols (0.17 [0.17] vs. 0.09 [0.04]; P < 0.01) were significantly higher in infants fed human milk than in those receiving formula.

CONCLUSION

Healthy, full-term infants fed formula without preformed dietary long-chain polyunsaturated fatty acids are unable to match the arachidonic and docosahexaenoic acid status of breast-fed infants even during the second half of the first year of life.

Docosahexaenoic and arachidonic acid absorption in preterm infants fed LCP-free or LCP-supplemented formula in comparison to infants fed fortified breast milk

The absorption of long-chain polyunsaturated fatty acids (LCP) with particular respect to docosahexaenoic (DHA) and arachidonic acid (AA) has been studied in 39 very-low-birth-weight infants appropriate for gestational age after a 10-day feeding period. The infants were fed either a LCP-supplemented formula (n = 11), or a LCP-free formula (n = 11) or breast milk fortified with protein and carbohydrates to have similar protein and energy intakes as in the formula-fed infants (n = 17). Total fat content and fatty acid profile were measured in the human milk, the two formulas, and in the stool samples. After a 10-day feeding period, the fecal excretions of total fat, DHA and AA were measured during a 3-day balance period. The total fat apparent absorption rates were similar in all groups (84.1, 82.1 and 80.6% of intake, respectively). The DHA and AA intakes were significantly (p < 0.01) higher in the group fed the fortified breast milk than in the group fed the LCP-supplemented formula (DHA: 75.5 +/- 12.4 vs. 50.2 +/- 4.2 mg/72 h; AA: 45.5 +/- 5.8 vs. 30.2 +/- 2.7 mg/72 h). There was a tendency for lower apparent absorption rates for both LCPs studied in the group fed fortified breast milk when compared to the group fed LCP-supplemented formula (AA: 70.6 +/- 10.9 vs. 73.0 +/- 8.7% of intake, DHA: 69.0 +/- 10.6 vs. 74.2 +/- 9.5% of intakes, but the differences were not significant. As consequence of the different intakes, the net absorption of the two studied LCP fatty acids were significantly (p < 0.01) higher in the breast milk group than in the group fed the LCP-supplemented formula (DHA: 52.6 +/- 6.1 vs. 36.8 +/- 4.5 mg/72 h; AA: 31.4 +/- 3.1 vs. 22.4 +/- 2.3 mg/72 h). The data demonstrate that DHA and AA are absorbed from the studied LCP-supplemented formula at least as effectively as from human milk. The net absorption of these LCP depend on the amount of dietary intake, and seems to be influenced by the dietary LCP source.

[In vivo investigations of stress susceptibility in pigs by means of magnetic resonance spectroscopy]

31P nuclear magnetic resonance spectroscopy was performed on 19 to 55 kg weighing pigs of different MHS genotypes to study the changes of phosphorus components (inorganic phosphate --Pi, phosphocreatine--PCr and adenosine triphosphate--ATP) of muscle metabolism as well as intramuscular pH under application of halothane. Aim of the present study was to observe the changes in energy metabolism and to perform a comparison with also measured blood parameters. Both, NN and Nn pigs did not show any changes during halothane exposure in phosphorus spectra, but in all animals a partially metabolically compensated respiratoric acidosis was found. In all MHS positive pigs a rapid fall of PCr and a corresponding raise of Pi levels in muscle was observed.

[3-13C] gamma-linolenic acid: a new probe for 13C nuclear magnetic resonance studies of arachidonic acid synthesis in the suckling rat

Our objective was to develop a suitable probe to study metabolism of polyunsaturated fatty acids by 13C nuclear magnetic resonance (NMR) in the suckling rat pup. [3-13C] gamma-Linolenic acid was chemically synthesized, and a 20 mg (Experiment 1) or 5 mg (Experiment 2) dose was injected into the stomachs of 6-10-day-old suckling rat pups that were then killed over a 192 h (8 d) time course. 13C NMR showed that 13C in gamma-linolenate peaked in liver total lipids by 12-h post-dosing and that [5-13C]-arachidonic acid peaked in both brain and liver total lipids 48-96 h post-dosing. 13C enrichment in brain gamma-linolenic acid was not detected by NMR, but gas chromatography-combustion-isotope ratio mass spectrometry showed that its mass enrichment in brain phospholipids at 48-96 h post-dosing was 1-2% of that in brain arachidonic acid. 13C was present in liver and brain cholesterol and in perchloric acid-extractable water-soluble metabolites in the brain, liver and carcass. We conclude that low but measurable amounts of exogenous gamma-linolenic acid do access the suckling rat brain in vivo. The slow time course of [5-13C] arachidonic acid appearance in the brain suggests most of it was probably transported there after synthesis elsewhere, probably in the liver. Some carbon from gamma-linolenic acid is also incorporated into lipid products other than n-6 long-chain polyunsaturated fatty acids.

Influence of the derivatization procedure on the results of the gaschromatographic fatty acid analysis of human milk and infant formulae

Many different analytical procedures for fatty acid analysis of infant formulae and human milk are described. The objective was to study possible pitfalls in the use of different acid-catalyzed procedures compared to a base-catalyzed procedure based on sodium-methoxide in methanol. The influence of the different methods on the relative fatty acid composition (wt% of total fatty acids) and the total fatty acid recovery rate (expressed as % of total lipids) was studied in two experimental LCP-containing formulae and a human milk sample. MeOH/HCl-procedures were found to result in an incomplete transesterification of triglycerides, if an additional nonpolar solvent like toluene or hexane is not added and a water-free preparation is not guaranteed. In infant formulae the low transesterification of triglycerides (up to only 37%) could result in an 100%-overestimation of the relative amount of LCP, if these fatty acids primarily derive from phospholipids. This is the case in infant formulae containing egg lipids as raw materials. In formula containing fish oils and in human milk the efficacy of esterification results in incorrect absolute amounts of fatty acids, but has no remarkable effect on the relative fatty acid distribution. This is due to the fact that in these samples LCP are primarily bound to triglycerides. Furthermore, in formulae based on butterfat the derivatization procedure should be designed in such a way that losses of short-chain fatty acids due to evaporation steps can be avoided. The procedure based on sodium methoxide was found to result in a satisfactory (about 90%) conversion of formula lipids and a reliable content of all individual fatty acids. Due to a possibly high amount of free fatty acids in human milk, which are not methylated by sodium-methoxide, caution is expressed about the use of this reagent for fatty acid analysis of mothers milk. It is concluded that accurate fatty acid analysis of infant formulae and human milk requires a careful and quantitative derivatization of both polar and nonpolar lipid classes. Sodium methoxide seems to be a reliable and time-saving method for routine fatty acid analysis of infant formulae, which should be validated by interlaboratory comparison. Anhydrous procedures based on methanolic hydrogen chloride including an additional nonpolar solvent are also suitable for infant formulae but seem to be preferable for human milk samples.

Docosahexaenoic and arachidonic acid content of serum and red blood cell membrane phospholipids of preterm infants fed breast milk, standard formula or formula supplemented with n-3 and n-6 long-chain polyunsaturated fatty acids

The contents of docosahexaenoic (DHA) and arachidonic acid (AA) of plasma and red blood cell membrane phospholipids were studied in 41 very low birth weight infants fed either breast milk (n = 18), a standard formula without long-chain polyunsaturated fatty acids with 20 or 22 carbon atoms (LCP) but with alpha-linolenic acid and linoleic acid (n = 11) or a formula additionally supplemented with n-3 and n-6 LCP in relations typical for human milk (n = 12) after 2, 6, and 10 weeks of feeding. The content of DHA and AA in plasma phospholipids declined in the infants fed the LCP-free formula but remained more or less constant during the whole feeding period in those infants fed breast milk as well as in those fed the LCP-supplemented formula. The differences between the group fed the LCP-free standard formula and the two groups fed LCP-containing diets became significant during the first 2 weeks of feeding. In contrast, there were no differences between the group fed breast milk and the group fed the supplemented formula during the study period. Similar effects could be observed regarding the composition of red blood cell membrane phospholipids, but the differences between the infants fed the LCP-free standard formula and the two other groups with LCP-containing diets were significant only for AA. The data indicate that very low birth weight infants are unable to synthesize LCP from alpha-linolenic acid and linoleic acid in sufficient amounts to prevent a decline of LCP in plasma and red blood cell phospholipids. Additionally, the data show, that supplementation of formulas with n-3 and n-6 LCP in amounts typical for human milk fat results in similar fatty acid profiles of plasma and red blood cell membrane phospholipids as found during breast milk feeding.

CONCLUSION

Supplementation of formula with long-chain polyunsaturated fatty acids improves the LCP status of very low birth weight infants.

Bilateral ulna hypoplasia, club feet, and mental retardation: a new mesomelic syndrome

We report on 2 sibs with a previously unreported type of mesomelia of the upper limbs due to ulnar hypoplasia. Prenatal diagnosis was made by ultrasound during one pregnancy and an affected fetus was confirmed. This family documents a previously unreported autosomal recessive syndrome.

Pitfalls in the design and manufacture of infant formulae

The composition of modern infant formulae is basically oriented on the "golden standard" human milk and influenced by several official regulations and recommendations (EC, ESPGAN, etc.). This article will focus on two recent improvements in the field of long-chain polyunsaturated fatty acids (LCPs) and protein hydrolysates. The addition of LCPs for preterm formulae was recommended recently by ESPGAN (the European Society for Pediatric Gastroenterology and Nutrition). Our research has focused on this problem for many years and we have found a good source of LCPs using specially prepared egg-yolk lipids. Others have used fish oils and run into the problem of growth retardation. Therefore, the possible sources of LCPs have to be discussed very critically and the alternatives will be shown. Also, new developments like the use of single-cell oils will be discussed. Second, the use of protein hydrolysates have been introduced for the so-called hypoantigenic or hypoallergenic formulae. Hypoantigenic formulae for preventive use have to be differentiated clearly from hypoallergenic formulae for treatment of proved cows' milk protein allergy. The problems of designing suitable hydrolysates that are low in antigenicity and good in taste will be outlined. The determination of the molecular weight distribution by gel chromatography will be compared critically with the newer techniques. The ELISA technique for testing the antigenicity is recommended before any in vivo evaluation. So far, the anaphylactic guinea-pig model is the most sensitive in vivo testing method. Summing up, modern infant formulae manufacture is much more dependent on modern laboratory techniques, which have to be chosen critically and must be adapted to the newest state of the art.

Diet and the essential fatty acid status of term infants

Long-chain polyunsaturated fatty acids with 20 and 22 carbon atoms (LCPs) seem to play an important role during the rapid development of the infant brain in the late fetal and early postnatal period. These LCPs are integral constituents of biological membranes and they are involved in the regulation of functional properties like fluidity, permeability and activity of membrane-bound enzymes. Human milk contains LCPs in an amount of 0.5-3 wt% of total fatty acids, whereas commercially available infant formulae are almost free of them. Recently, several clinical trials, primarily with preterm infants, have reported that the content of LCPs in the blood and a functional parameter like visual acuity correlate with the content of LCPs in the diet. In this clinical trial we studied the effect of different diets on the fatty acid pattern of plasma and erythrocyte lipids of healthy term infants during the first 3 months of life. Breast-fed infants were compared with formula-fed babies who received a commercially available formula without LCPs or a new experimental formula enriched with LCPs that was similar to human milk. The results indicate that the introduction of milk feeding leads to marked differences in the blood lipid composition during the first months of life, independent of the feeding regimen. Secondly, the supplementation of a formula with LCPs seems to result in a blood lipid composition similar to infants fed with human milk. This supports the hypothesis that the newborn term infant has a limited desaturating capacity and depends on an exogenous supply of LCPs during the first months of life.

Specific molecular prenatal diagnosis for the CTG mutation in myotonic dystrophy

The results of DNA analysis for the specific mutation of myotonic dystrophy are reported in eight pregnancies (two studied retrospectively) in six families. Four results were normal; in the other four, large DNA expansions were found, comparable to the range seen in severely affected children with congenital onset of the disorder. The results agreed with those obtained by linked DNA markers in the six cases where they were available. We conclude that specific molecular prenatal diagnosis of myotonic dystrophy is feasible, and that an abnormal result may also give a guide to possible severity, though this should be interpreted with caution until greater experience is available.

Placental insufficiency as a possible cause of low maternal serum human chorionic gonadotropin and low maternal serum unconjugated estriol levels in triploidy

We report three cases in which triploidy (69,XXX) was detected by amniocentesis performed for very low maternal serum human chorionic gonadotropin levels. All three cases also had low maternal serum unconjugated estriol levels. We suggest placental insufficiency as the cause of the very low human chorionic gonadotropin because of histologic observations and because a known marker for placental insufficiency, estriol, was also very low.

The dilemma of a low rate of chromosomal mosaicism found in fetal blood sampling

We report a case in which mosaicism of trisomy 13 was detected in 4/10 cells (40 per cent) in amniotic fluid cell cultures, followed by a low rate of mosaicism (1/160 cells) detected in a fetal blood sample. This finding presents a dilemma both for the genetic counsellor and for the parents in determining whether or not to terminate the pregnancy.

Nevus flammeus. Discordance in monozygotic twins

Nevus flammeus has been described as an inherited vascular anomaly. We report two cases of nevus flammeus, each appearing in one of two monozygotic twins. This finding supports the idea that nevus flammeus results from embryologic mishap rather than genetic transmission.

Establishment of a human T-acute lymphoblastic leukemia cell line with a (16;20) chromosome translocation

A new T-cell line, Loucy, was established from the peripheral blood of a patient with T-cell acute lymphoblastic leukemia (T-ALL). The surface marker analysis of the cell line is OKT3+, OKT4+, THB4+, J5 +/-, OKT6-, TdT-, and HLA-DR-, indicating stage IV in T-cell lineage. Karyotype analysis revealed 45,X,5q-,t(16;20)(p12;q13). The translocation between chromosomes 16 and 20 has not been previously detected in ALL. This cell line may be of value in evaluating the role of t(16;20) in the etiology of T-ALL.

Congenital hereditary hypothyroidism--prenatal diagnosis and treatment

Intrauterine diagnosis of congenital hypothyroidism was established on the basis of TSH concentration in amniotic fluid in the 22nd week of gestation for the offspring of a couple both known to have an iodide organification defect. Prenatal treatment consisted of intramniotic injections of 500 mcg Na-1-thyroxine, which was administered from the first amniocentesis until one week before delivery. Following delivery, the diagnosis was confirmed by the elevated level of TSH, 60.5 uU/ml, and a gradual decrease of fT4 to 0.8 ng/ml. Regular substitution therapy was commenced on the third day of life. The normal shape and location of the thyroid gland was demonstrated by Technetium scintiscan. At 18 months the infant revealed no significant deviation from normalcy in growth or mental capacity. This experience indicates that testing of amniotic fluid for TSH in the 22nd week of gestation can be diagnostic for congenital primary hypothyroidism. Furthermore, it is suggested that the treatment approach described is warranted in all cases in which there is a high risk of congenital primary hypothyroidism.

Tetrasomy 18p in a child with trisomy 18 phenotype

We report on a patient with trisomy 18 syndrome and tetrasomy 18p. The case indicates that the presence of an isochromosome i(18p) can mimic complete trisomy 18 syndrome.

Determination of surface bound and shed HLA antigens of amniotic cells by ELISA

HLA typing of amniotic cells for clinical purposes using the conventional cytotoxicity assay is a laborious and complicated procedure. In the present study we demonstrate that HLA class I typing of the fetus can be determined using the enzyme linked immunosorbent assay (ELISA) either on amniotic cells or soluble free antigens shed by the cells into the culture medium. Our results indicate that the ELISA technique is a sensitive and reliable assay that can be used as an alternative method of HLA class I typing of amniotic cells.

Muscle involvement in mucolipidosis IV

A 15-month-old boy, thought to have a congenital myopathy, was subsequently diagnosed as having mucolipidosis type IV, with typical membranous inclusions in muscle fibers. Involvement of skeletal muscle in this lysosomal storage disease may explain the motor delay and hypotonia that are its most common presenting signs.

New type of autosomal recessive short-limb dwarfism with absent fibulae, exceptionally short digits, and normal intelligence

Short-limb dwarfism is of heterogeneous origin and has various clinical manifestations. This communication describes a previously apparently unreported type of short-limb dwarfism in 3 affected sibs. Characteristics of this syndrome are bilateral absence of fibulae and severe abnormalities of all digits.

Aplasia of the tibia with bifurcation of the femur and ectrodactyly: evidence for an autosomal recessive type

Two unrelated families are presented, each with 2 affected offspring with bifid femur, absent tibia, and ectrodactyly. The healthy parents are consanguineous. It is postulated that this combination of malformations is causally heterogenous with both autosomal dominant and autosomal recessive modes of inheritance; hence, it is established as a developmental field defect.

Chorionic villi sampling for early prenatal diagnosis: an option for the Jewish orthodox community

The Jewish religion permits abortion up to 40 days after conception. To accommodate the Jewish orthodox community, prenatal diagnosis in the eighth gestational week may be a feasible goal with clear benefits. We present our experience with chorionic villus sampling (CVS), wherein out of 144 patients requesting CVS, 125 were found to be suitable for the procedure. Excluding patients with fundal placenta and cervical or uterine myoma, chorionic sampling was successfully performed on 102 out of 106 patients (96.2%) and a chromosome result was available for 98 of those patients (96%). Fetal losses, within 14 days following procedure, were 2 out of 125 (1.6%). No complications were encountered following the procedure. The cytogenetic analysis was improved by culturing CVS fragments for 48 h, after which clearer banding patterns could be observed. One of the CVS preparations, from a 7.2/7-week-old embryo was successfully examined. Short-term (6 days) cultures were used as an additional method for chromosome analysis, to extend and confirm results obtained by the direct method.

New chromosome aberration: duplication of a large part of chromosome 4q and partial deletion of chromosome 1q

We describe a preterm female infant with multiple anomalies who has a duplication of a large part of 4q and partial deletion of chromosome 1q. Her karyotype was interpreted to be 46,XX,-1,+der(1),t(1;4) (q44;q23 or 24)mat. She is the first patient with an unbalanced translocation involving chromosomes 4 and 1. There is a substantial amount of concordance between the phenotypic features of this patient and those described in the context of partial deletion 1q. The extensive duplication of 4q has no dominant clinical effects in the present infant. These facts support the general concept of much more deleterious effects of deletions versus duplications in human species.

Ring 18 chromosome with mental retardation, hemidysmorphism, and mitochondrial encephalomyopathy

A 2 1/2-year-old female is reported with ring 18 chromosome syndrome. The chromosomal abnormality was found in all examined leukocytes and cultured skin fibroblasts. Besides the usual clinical characteristics of this syndrome, two additional features are described that have not been reported previously: right hemidysmorphism, including hypertrophy of the tongue and lower extremity; coloboma of the lower right side of the gums; atretic external right ear canal; and hypotonia with mitochondrial encephalomyopathy associated with excessive ketonemia during normal food intake and a large increase after overnight fast.

Isolated "clinical anophthalmia" in an extensively affected Arab kindred

A highly inbred kinship is described, in which 19 individuals were afflicted with bilateral profound microphthalmia without associated anomalies and with normal intelligence. Autosomal recessive inheritance is demonstrated. This kindred is instructive for genetic counseling since the affected individuals always have bilateral microphthalmia in the absence of other affected organ systems.

Clinical Spectrum of Mucolipidosis Type IV

To the Editor.—

We read with interest the presentation by Amir et al1 concerning the clinical spectrum and natural history of mucolipidosis type IV. Based on their experience with 20 patients, they try to provide guidelines for the clinical diagnosis of this lysosomal storage disease. It appears that severe visual impairment (due mainly to corneal opacities, myopia, and retinal degeneration) and psychomotor retardation are the cardinal features of this entity.

However, corneal clouding and mild motor delay in their early stages may frequently be missed by even experienced pediatricians and we recently examined a 15-month-old boy who was referred to us for evaluation of a possible congenital myopathy.

Hereditary hypotrichosis simplex of the scalp

Hereditary hypotrichosis simplex of the scalp is a rare trait with onset in early childhood. This phenomenon has been reported only once previously, in a Spanish kindred. This communication describes a case in a Jewish-Yemenite kindred with 51 affected individuals and confirms autosomal dominant inheritance.

Spondyloepiphyseal dysplasia tarda: a new autosomal recessive variant with mental retardation

A new variant of spondyloepiphyseal dysplasia tarda with mild to moderate mental retardation is described in three daughters born to healthy, consanguineous parents. The mode of inheritance is compatible with that of an autosomal recessive disorder. The identification of this variant is important, as it enables more precise counselling in families in which sporadic cases with this form of presentation are found.

The amniotic band syndrome: a possible complication of amniocentesis

Malformations of the upper distal extremities were noted in an otherwise healthy infant whose mother underwent diagnostic amniocentesis. A causal relationship is postulated.

Trisomy 18 mosaicism in an adult with normal intelligence

A healthy 30-year-old woman was discovered unexpectedly to have trisomy 18/normal chromosome mosaicism. She was ascertained because of a history of three spontaneous abortions following the birth of a healthy son. Trisomy 18 was present in 18% of her lymphocytes and 2% of her cultured skin fibroblasts. She had several minor malformations associated with trisomy 18 syndrome. She is, to our knowledge, the first person who has clinical stigmata of trisomy 18 but has normal intelligence and leads a normal family life.

Partial deletion of the short arm of chromosome 3: further delineation of the 3p25-3pter syndrome

A male newborn with partial deletion of the short arm of chromosome 3 is described. The patient shares most of the features with the previously reported cases. In addition, cardiac, skeletal and gastrointestinal anomalies not previously reported are described. These characteristics may help in further delineation of the syndrome.

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase deficiency: gender reassignment in early infancy

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) deficiency has a high prevalence within the Arab population of the Gaza strip and is characterised by marked virilization at puberty, leading in many cases to the spontaneous adoption of a male gender role. As a result of this, parents of 7 affected male infants (aged 1-10 months) born with female phenotype requested early gender reassignment. Diagnosis was suspected in 5 on the basis of a positive family history, but confirmed in all cases by the finding of low to normal testosterone levels (30-184 ng/dl) with high delta 4-androstenedione levels (188-808 ng/dl), after hCG. Treatment with im testosterone oenanthate (25-50 mg/dose) was given in one to three 3-months courses and penile size was increased into the normal range without evoking a significant increase in height velocity or skeletal maturation. Five patients underwent the first stage of male genitoplasty between 2 and 3 years of age. This consisted of bilateral orchidopexy, chordee release and penile lengthening - yielding finally an anatomically normal-sized and shaped penis. Androgen responsive male pseudohermaphroditism due to 17 beta-HSD deficiency or a similar defect and diagnosed in infancy should be treated as soon as possible with systemic testosterone before considering any sex change, and in preparation for male genitoplasty. Early gender reassignment according to genetic and gonadal sex is probably the management of choice for these cases since this may result in a normal adjustment to the male gender role, particularly after puberty.

Incorporation of [14C]glucose into alpha-1,4 bonds of glycogen by leukocytes and fibroblasts of patients with type III glycogen storage disease

In two patients assay of alpha-1,6-amyloglucosidase activity by incorporation of [14C]glucose into glycogen revealed normal activity in leukocytes, erythrocytes, and fibroblasts, whereas no activity was detected in liver and muscle. No activity in any tissue was found when enzyme activity was assayed by following the release of glucose from a phosphorylase limit dextrin. Labeling of glycogen by incubation with crude tissue homogenates according to the protocol used for the [14C]glucose method and subsequent degradation of the outer portion of the polysaccharide molecule with beta-amylase showed that with tissues from normal controls more than 90% of the label of the glycogen was retained in the limit dextrin. When fibroblasts or leukocytes of the patients served as enzyme source up to 80% of the label was released after incubation with beta-amylase or phosphorylase a. Addition of Tris to the assay inhibited enzyme activity in fibroblast homogenates of the patients and of controls to the same extent and had no effect on the distribution of the label between supernatant and limit dextrin after beta-amylolysis of the labeled glycogen. A pH curve performed with fibroblast preparations from the patients and a normal control did not reveal differences in the effect of changes in pH on [14C]glucose incorporation. We propose that incorporation of [14C]glucose into glycogen by the enzyme present in the patients' cells was into alpha-1,4 linkages in glycogen.

Cystine accumulation and clearance in normal and cystinotic fibroblasts exposed to cystine dimethyl ester

Exposure of cultured skin fibroblasts of normals and cystinotic patients to 0.5 mmol/l[35S]cystine dimethyl ester for 30 min resulted in an accumulation of cystine in excess to that naturally occurring in cystinotic skin fibroblasts. These equal levels of cystine accumulation achieved in both cystinotic and normal cells, permitted comparative experiments to look for differences in cystine disposal between normal and cystinotic cells. Cystinotic fibroblasts demonstrated very low cystine clearance with a lower ratio of cysteine-N-ethylmaleimide to cystine than normal. The results on cystinotic fibroblasts are consistent with those observed in leucocytes, suggesting that fibroblasts can be useful in further studies to elucidate the clearance defect of cystine in cystinosis as well as its potential in antenatal diagnosis.

Comparative study of cystine clearance in cystinotic and I-cell fibroblasts upon exposure to cystine dimethyl ester

I-cell fibroblasts can accumulate cystine at levels comparable to those seen in homozygous cystinotic fibroblasts. Cystine accumulation in cystinosis is accounted for cystine clearance defect in situ. To unravel the question whether the same clearance defect or two different mechanisms cause cystine accumulation in I-cell disease, we used the cystine loading technique upon exposure of skin fibroblasts to radioactive cystine dimethyl ester. Normal, cystinotic and I-cell fibroblasts were exposed to radioactive cystine dimethyl ester, and the clearance of the generated radioactive cystine was measured. Cystinotic cells showed a marked defect in cystine clearance in situ, as compared to normal fibroblasts. In I-cell fibroblasts, we observed slow hydrolysis of cystine dimethyl ester to cystine, indicating low esterase activity, but no defect in clearance of the generated cystine. Cysteine production from the exogenous cystine dimethyl ester, presumably by cytoplasmic hydrolysis of the generated cystine, is normal in I-cell fibroblasts. Thus, our results indicate that, unlike cystinosis, there is no cystine clearance defect in situ for cystine in I-cell disease, and probably unrelated mechanisms cause cystine storage in cystinosis and I-cell disease.

Dominant ano-rectal malformation, nephritis and nerve-deafness: a possible new entity?

A family is presented in which ano-rectal malformation and features common to Alport Syndrome appear to be present in three generations. The possibility of a new syndrome based on a single gene defect is discussed.

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase deficiency: studies on the natural history of the defect and effect of androgens on gender role

Studies within the Arab population in Israel revealed 25 pseudohermaphrodites due to 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) deficiency. Twenty-three individuals, presently living in the Gaza strip, belong to a very large inbred kinship which extends over 8 generations. All affected subjects (46, XY) were born with mild to moderate degrees of ambiguity of an apparently normal-looking female genitalia and therefore were reared as girls. In childhood, genital abnormalities consisted of a clitoral-like phallus surrounded by a chordee, non-fused labial-scrotal folds and a urogenital sinus. The testes were in the inguinal canals, or rarely, in the labial-scrotal folds. Wolffian structures were normally differentiated while Mullerian structures were absent. At puberty, subjects developed a male body habitus with abundant body hair and beard. Gynecomastia was absent. The phallus and testes enlarged to adult proportions while the prostate remained small. Together with the physical change from girls to boys they developed a male identity having erections and ejaculations, which in 7 cases led to the spontaneous adoption of a male gender role. In adults the hormonal abnormalities consisted of greatly elevated delta 4-androstenedione (delta 4) (350-1267 ng/dl) associated with subnormal testosterone (T) levels (0.9-3.1 ng/ml). Dihydrotestosterone (DHT) levels, with the exception of 1 patient, were relatively low in all cases (27-35 ng/dl). Children had low levels of delta 4, T and DHT, which were normal for age. Although from puberty on there was a significant rise of the 3 androgens, delta 4 always remained extremely elevated and T and DHT relatively low when compared to normal controls. Dexamethasone failed to suppress the androgen pattern while HCG augmented the defect, making the diagnosis possible in 2 prepubertal children. Dehydroepiandrosterone (DHEA) and 17-hydroxyprogesterone (17-OHP) levels were normal or moderately elevated. Estradiol (E2) levels were normal in children and all but 2 adults, who had high levels. LH and FSH levels were very high after puberty, but normal before. However, there was an overresponse to LHRH in all age groups. The contrast between the lack of intrauterine virilization of the external genitalia in fetuses with 17 beta-HSD deficiency versus the marked masculinization that occurs after puberty still remains a puzzling phenomenon. It is conceivable that the postpubertal development of a male phenotype with change of gender identity and role occurs due to the joint effect of delta 4, T and DHT, even though secreted in inadequate proportions. Thus masculinization in these individuals is a slow process requiring a longer period of time than that of normal puberty to be completed.

Can infantile hereditary agranulocytosis be diagnosed prenatally?

Fetoscopy and fetal blood sampling were performed in an attempt at prenatal monitoring of a pregnancy at risk for infantile hereditary agranulocytosis (Kostmann's disease). In smears of fetal blood three segmented neutrophils were found out of 200 nucleated cells (1 1/2 per cent). Their presence, although in a lower percentage than in six age-matched controls, was considered to indicate that the fetus was not affected. The newborn infant has developed normally and at the age of four months has a normal number of segmented neutrophils in his peripheral blood. Feasibility of prenatal diagnosis of infantile hereditary agranulocytosis is discussed.