The efficacy and safety of long-term Norditropin® treatment in children with Prader-Willi syndrome

Prader-Willi syndrome is a genetic disorder that is associated with short stature, partial growth hormone deficiency, small hands and feet, learning and behavioural problems, and hyperphagia leading to severe, often morbid, obesity. Growth hormone therapy is associated with an improvement in height and body composition. We evaluated the efficacy and safety of long-term growth hormone treatment in a retrospective observational multinational study of 41 prepubertal children (mean age 3.8±3.0 years) with genetically diagnosed Prader-Willi syndrome treated with growth hormone (0.03-0.06 mg/kg/day) for >12 months [mean duration 4.1 (range 0.9-9.5) years]. Height, weight, and body composition measurements were recorded at baseline and at 6 month intervals until last observation. Mean (SD) gain in height at 12 months was 0.9 (0.2) SD score (p<0.0001). At last observation (after approximately 6 years) mean gain in height was 1.3 (0.3) (p=0.0001) with 85% of children achieving height>- 2 SD score. Body composition improved during treatment with an estimated 9.1% increase in lean body mass and 9.1% decrease in fat mass at last observation (p=0.019). Scoliosis was reported in 3 patients at baseline and 8 patients at last observation. Sleep apnoea was recorded in 3 (7.3%) patients. There were no other severe adverse events reported. Long-term growth hormone treatment of prepubertal children with Prader-Willi syndrome was associated with significant improvements in height and body composition. Treatment was well tolerated. The development of scoliosis warrants monitoring by an orthopaedic specialist.

Behavioural and emotional disturbances in people with Prader-Willi Syndrome

BACKGROUND

The study of the behaviour profile in subjects with Prader-Willi Syndrome (PWS).

METHODS

A total of fifty-eight 3- to 29-year-old subjects with PWS were studied using a standardized parent report of behavioural and emotional disturbances.

RESULTS

There was an increase of behavioural and emotional disturbances for the adolescent and young adult age range, whereas gender and intelligence were not significant. Increasing body mass index (BMI) was also associated with more behavioural and emotional disturbances. There was no significant relation between genetic status and behavioural abnormalities.

CONCLUSIONS

This systematic study supports single case observations of a heightened psychiatric vulnerability of adolescent and young adult PWS subjects.

Body composition abnormalities in children with Prader-Willi syndrome and long-term effects of growth hormone therapy

Obesity and hypothalamic GH deficiency contribute in different ways to the disturbances of body composition in Prader-Willi syndrome (PWS); while both increase the fat compartment, the reduction of lean tissue mass has been attributed mainly to GH deficiency. Therefore, body composition measured by dual-energy X-ray absorptiometry was prospectively studied in 12 overweight children with PWS and weight for height (WfH) SDS >0 before and during 3.5 years of treatment with hGH (0.037 mg/kg/day) on average. In the long term, there is a net reduction of body fat from 3.1 to 1.2 SD, with a minimum at the end of the second year of treatment. WfH SDS correctly reflects body fat mass and its changes. The initial deficit of lean mass (-1.6 SD) is counteracted by GH only during the first year of therapy (increase to -1.25 SD). But in the long term, GH therapy does not further compensate for this deficit, when lean mass is corrected for its growth-related increase. In conclusion, exogenous GH changes the phenotype of children with PWS: fat mass becomes normal, but, at least in the setting studied, GH is not sufficient to normalize lean tissue mass.

Growth hormone normalises height, prediction of final height and hand length in children with Prader-Willi syndrome after 4 years of therapy

BACKGROUND

Based on the reported favourable effects of growth hormone (GH) treatment on growth and body composition in Prader-Labhart-Willi syndrome, we studied age dependency and the long-term effects on growth dynamics to elucidate the assumed hypothalamic GH deficiency.

METHODS

We examined 23 children treated with hGH (24 U/m(2)/week) during a median of 4 (range 1.5-5.5) years; group 1: 10 young underweight (age 0.3-4.1 years), group 2: 8 prepubertal overweight (age 3.7-9.5 years) and group 3: 5 pubertal overweight children (age 9.0-14.6 years).

RESULTS

After 4 years of therapy, height gain amounted to 1.8 SD; height (0.0 SD) and hand length (-0.2 SD) were normalised in the 2 prepubertal groups; in children above 6 years, height prediction approached parental target height. Weight for height rose in group 1 (to 0.64 SD) and decreased in group 2 (to 0.71 SD) to normal levels. Bone maturation of the pubertal children was too advanced to show a clear growth response to GH (height gain 0.42 SD). Even in this group, weight for height was reduced, but remained supernormal.

CONCLUSION

Under exogenous GH, growth and body proportions are normalised in prepubertal children. With early institution of treatment, final height prediction reaches the parental target height range after 3 years. Such a growth-promoting effect of exogenous GH has so far only been described in children with GH deficiency.

Early manifestations of Prader-Willi syndrome: influence of growth hormone

Pediatricians and neonatologists now understand the clinical picture of Prader-Willi syndrome (PWS) in infants as genetic tools are available to confirm this diagnosis. Hence, an increasing number of very young, still underweight children are being diagnosed with PWS. Some features, such as low prenatal weight and below-average height, subsequent poor growth velocity and increased body fat, possibly in infancy, may be interpreted as a consequence of early growth hormone (GH) deficiency. This raises the question of when is the best time for the initiation of GH treatment. This article presents the results of a study in which ten very young children with PWS (mean age 1.0 year) were treated with exogenous GH. We conclude that GH treatment in young, underweight children, as well as in older children with PWS: (1) normalizes growth and body proportions; (2) probably reduces fat mass and increases muscle mass; (3) may enhance motor development; and (4) is necessary, but obviously not sufficient, to normalize body composition and fat distribution. Whether there is a benefit in treating children with PWS from such an early age requires longer-term studies.

Cardiovascular risk factors improve during 3 years of growth hormone therapy in Prader-Willi syndrome

Cardiovascular risk factors in Prader-Willi syndrome (PWS, OMIM 176270) may be independently caused by overweight or hypothalamic growth hormone (GH) deficiency. The present observational study in 23 children with PWS, aged 0.3-14.6 years, focuses on the specific pattern, age-dependency and interrelation of cardiovascular risk factors, namely percentage fat mass and regional fat distribution, triglycerides (TG), lipoprotein cholesterols (LDL-C, HDL-C), lipoprotein (a) (Lp(a)), apolipoproteins A-I (Apo A-I) and B (Apo B), as well as on the longer-term effects of GH therapy (ca. 0.037 mg/kg per day for 3 years on average). We report that in children above 4 years, percentage body fat was increased in all and waist-to-hip-ratio (WHR) in 35%. Abnormal levels of LDL-C, Apo B, HDL-C and TG were found in 6, 7, 6 and 3 children, respectively. Lp(a) was above 300 mg/l in 5 patients and remained unchanged during GH therapy. However, percentage fat mass dropped to the upper normal range and WHR became normal in all patients receiving GH therapy, as did the ratio of LDL-C to HDL-C, subsequent to decreasing LDL-C and increasing HDL-C. Nevertheless, we could not find any significant correlation between parameters of total fat mass or fat distribution and serum lipid parameters, except for abdominal fat distribution (trunk-/leg-fat ratio) to TG before therapy.

CONCLUSION

Several cardiovascular risk factors are already present in prepubertal children with Prader-Willi-syndrome and they are improved by growth hormone treatment, acting both on body composition and lipid metabolism.

Is there growth hormone deficiency in prader-willi Syndrome? Six arguments to support the presence of hypothalamic growth hormone deficiency in Prader-Willi syndrome

Prader-Labhart-Willi syndrome (PWS) is the most frequent form of syndromal obesity. Its main features are associated with hypothalamic dysfunction, which has not yet been comprehensively described. The aim of this review is to present arguments to define the presence of genuine growth hormone (GH) deficiency (GHD) in these patients. Decreasing growth velocity despite the onset of obesity, reduced lean body mass in the presence of adiposity, small hands and feet, relatively low insulin-like growth factor-I and low insulin levels, as well as the dramatic effect of GH treatment on growth, support the presence of hypothalamic GHD in PWS. Even though it might be difficult to ultimately prove GHD in PWS because of the obesity-induced counterregulation, the hormonal situation differs from that in simple obesity. The effects of long-term therapies with GH on body composition in these patients are summarized. GH therapy dramatically changes the phenotype of PWS in childhood: height and weight become normal and there is a sustained impact on the net loss of body fat. We conclude that GHD may account for several features of PWS.

Familial dysalbuminemic hyperthyroxinemia in a Swiss family caused by a mutant albumin (R218P) shows an apparent discrepancy between serum concentration and affinity for thyroxine

Familial dysalbuminemic hyperthyroxinemia (FDH), is the most common cause of inherited increase in serum total T4 (TT4) in the Caucasian population. It is caused by a mutation (R218H) in the human serum albumin (HSA) gene, resulting in 10-fold higher affinity for T4 and, in heterozygous affected subjects, a TT4 level 2-fold higher than that in subjects expressing the wild-type HSA only. We now report FDH in a Swiss family, caused by HSA R218P, previously reported in subjects of Japanese origin. In this form of FDH, serum TT4 levels are 14- to 20-fold the normal mean, confirmed by measurements in serum extracts. TrT3 and TT3, concentrations are 7- and 2-fold above the mean, respectively. Thus, to maintain a normal free T4 level, the calculated affinity constant (Ka) of HSA R218P should be about 16-fold higher than that of HSA R218H. Surprisingly, the Ka values measured at saturation were similar: 5.4 x 10(6) and 6.4 x 10(6) mol/L(-1) for HSA R218H, respectively. To determine how subjects with HSA R218P and R218P maintain a euthyroid state despite the markedly high serum TT4, the concentration of dialyzable T4 was measured at increasing amounts of TT4. At a TT4 level equivalent to that found in the subjects with HSA R218P, the absolute FT4 concentrations were 40, 432, and 1970 pmol/L for sera expressing HSAs R218P, R218H, and wild type, respectively. Thus, the affinity of HSA R218P for T4 must be higher than that of R218H to produce an 11-fold difference in FT4 at the same concentration ofTT4 This difference was obliterated at saturating concentrations of TT4 used for the determination of Ka values by the method of Scatchard.

Male hypogonadism caused by homozygous deletion of exon 10 of the luteinizing hormone (LH) receptor: differential action of human chorionic gonadotropin and LH

We report the unique case of a patient with Leydig cell hypoplasia (LCH) type II caused by a genomic deletion resulting in the complete absence of exon 10 of the LH receptor (LHR). The patient presented at the age of 18 yr with retarded pubertal development, small testicles, and delayed bone maturation. LH was highly elevated, with very low serum testosterone levels. Genetic analysis revealed a homozygous deletion of approximately 5 kbp encompassing exon 10 of the LHR gene. Screening of family members demonstrated heterozygosity for the deletion, indicating autosomal recessive inheritance. At the time of examination, the patient displayed nearly normal male phenotype, but lacked pubertal development and was hypogonadal. Obviously, fetal male development sustained by hCG was normal, whereas LH action, important for pubertal development, was impaired. A hCG stimulation test induced testosterone biosynthesis and secretion within the normal range. Subsequently, hCG treatment was continued, resulting in an increase in testicular volume and the appearance of spermatozoa in the ejaculate after 16 weeks of treatment (5.3 million/mL). Despite highly elevated endogenous LH serum levels, the response to hCG indicates a possible dual mechanism of hormone binding and signal transduction for hCG and LH on a LHR that lacks exon 10. Furthermore, this patient represents the clinical counterpart of the normal male marmoset monkey (Callithrix jacchus), in which the expressed LHR lacks exon 10 in toto. This case provides important clinical insights about the possible role of exon 10 of the LHR in discriminating between LH and hCG actions.

Phenotypic heterogeneity of growth and psychometric intelligence in Prader-Willi syndrome: variable expression of a contiguous gene syndrome or parent-child resemblance?

Phenotypic variability in children with Prader-Willi syndrome (PWS) was investigated with respect to variable expression of the contiguous gene syndrome and trait variance. In a prospective study, parent/child resemblance of anthropometric and psychometric measures was analyzed in 22 children with PWS (11 females and 11 males; 18 deletions, 4 uniparental disomy (UPD)) and in a control group (88 females and 88 males). The average child-midparent Z-score difference for height in females was -1.9 and in males -0.9, head circumference -1.7 and -1.0, and body mass index (BMI) 2.3 and 2.7, respectively. Intellectual performance of females and males was, on average, -2.7 and -2.6 below maternal performance. Range and standard deviation were moderately increased for height and head circumference, doubled for BMI, and unchanged for IQ. Parent/child correlations for anthropometric and psychometric measurements in the study group did not significantly differ from those of the control group. Exceptions were higher correlations between mothers and daughters for height (P < 0.05) and BMI (P < 0.01), and lower correlations for head circumference between midparent values and daughters (P < 0.05) than in the control group. In conclusion, parent-child resemblance in growth and intellectual development among children with PWS was found to be comparable to that noted in the normal population, indicating a strong determination by trait variance. Children with PWS differed significantly with respect to a lower trait level and-with the exception of IQ-a larger variability. The latter may indicate a variable expression of the contiguous gene syndrome.

Symptomatic versus substitution growth hormone therapy in short children: from auxology towards a comprehensive multidimensional assessment of short stature and related interventions

There is an ongoing debate as to whether symptomatic growth hormone treatment (GHT) in short children without growth hormone deficiency (GHD) is justified, since there is no substitutional indication. The increasing evidence that final height cannot be normalized in these patients (e.g. in Ullrich-Turner syndrome) reinforces this controversy. We have focused on the empirical evidence on the psychosocial and physical meaning of being short in childhood as well as on the underlying assumptions of the different GHT indications. The indication for GHT in patients with non-GHD may be seen as a pharmacotherapeutic intervention in order to prevent the developmental, physical and psychosocial risks associated with short stature. This requires a qualitative shift in methodological assessment with respect to the psychosocial and physical impact of being short as well as of the potential benefit of new treatment indications in terms of a more comprehensive evaluation including health-related quality of life for these patients.

Body fat determined by skinfold measurements is elevated despite underweight in infants with Prader-Labhart-Willi syndrome

Body composition and leptin were studied in 13 young, still underweight and 10 older overweight children with Prader-Labhart-Willi syndrome. Not only the older overweight children but also the young underweight children had elevated skinfold standard deviation scores for body mass index and elevated body mass index adjusted leptin levels, suggesting relatively increased body fat despite underweight. Our data indicate that body composition in Prader-Labhart-Willi syndrome is disturbed already in infancy, long before the onset of obesity. Leptin production appears to be intact.

Low insulin, IGF-I and IGFBP-3 levels in children with Prader-Labhart-Willi syndrome

It is well established that insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3) and insulin are low in growth hormone deficiency, but due to their dependence on nutrition, they are elevated in healthy obese children. As the presence of growth hormone deficiency in Prader-Labhart-Willi syndrome (PWS) is still controversial, we studied insulin, IGF-I and IGFBP-3 levels in 19 children with PWS (age range 0.5-14.6 years). Serum concentrations of insulin (SDS: -0.7+/-0.9, P = 0.01) and IGF-I (SDS: -0.7+/-0.8, P = 0.002) were low, but IGFBP-3 (SDS: -0.3+/-1.2, P = 0.2) was normal compared to normal weight age-matched children. Since children with PWS are typically obese, insulin, IGF-I and IGFBP-3 levels should be compared to normal obese children who present increased levels of these hormones. In comparison to data of healthy obese children reported in the literature, not only IGF-I, but also IGFBP-3 levels are low and fasting insulin levels even very low, suggesting a growth hormone deficiency.

Longitudinal monthly body measurements from 1 to 12 months of age: a study by practitioners for practitioners. Zurich Association of Practicing Paediatricians

A longitudinal growth study with monthly measurements during the 1st year of life was conducted by nine paediatricians working in private practice in Zurich. Of 92 children, none was lost to the study and only 32 of 1104 planned visits were missed; the quality of the measurements was comparable to that of a specialised university clinic. Compared to the Zurich Longitudinal Growth Studies, children of this study were considerably heavier and taller. In 92% of the subjects, growth velocity was at least once outside the reference range (3rd 97th percentile). For weight increments, the corresponding proportion was 87%.

CONCLUSIONS

The data indicate that current standards for the 1st year of life for the Zurich area might no longer be appropriate and need to be updated. The currently used velocity percentiles based on 3-monthly measurements are not suitable to assess individual height and weight increments calculated from monthly measurements.

Treatment with human growth hormone in patients with Prader-Labhart-Willi syndrome reduces body fat and increases muscle mass and physical performance

Twelve children with documented Prader-Labhart-Willi syndrome were treated with human growth hormone (24 U/m2/week) during 1 year. The children were divided into three groups: group 1: overweight and prepubertal (n=6, age 3.8-7.0 years); group 2: underweight and prepubertal (n=3, age 0.6-4.1 years); group 3: pubertal (n=3, age 9.2-14.6 years). In group 1, height increased from -1.7 SD to -0.6 SD, while weight decreased from 1.1 SD to 0.4 SD, with a dramatic drop in weight for height from 3.8 SD to 1.2 SD. Hand length increased from -1.5 SD to -0.4 SD and foot length from -2.5 SD to -1.4 SD. Body fat, measured by dual X-ray energy absorptiometry, dropped by a third, whereas muscle mass increased by a fourth. Physical capability (Wingate test) improved considerably. The children were reported to be much more active and capable. In group 2, similar changes were seen, but weight for height increased, probably because muscle mass increase exceeded fat mass decrease. Changes in group 3 were similar as in group 1, even though far less distinct.

CONCLUSION

Growth hormone treatment in Prader-Labhart-Willi syndrome led to dramatic changes: distinct increase in growth velocity, height and muscle mass, as well as an improvement in physical performance. Fat mass and weight for height decreased in the initially overweight children, and weight for height increased in underweight children.

Effect of 6 months of growth hormone treatment in young children with Prader-Willi syndrome

Nine prepubertal children with Prader-Willi syndrome were treated with growth hormone (GH; 24 IU/m2/week) for 6 months. Mean height increased by 0.8 SD and mean weight for height decreased by 0.7 SD over this 6-month treatment period. Body fat, measured by dual-energy X-ray absorptiometry, decreased by 22.5% over the period of GH treatment, whereas fat-free mass increased by 14%. These preliminary results indicate that GH is effective in increasing height and normalizing body composition in patients with Prader-Willi syndrome.

Pit-1: clinical aspects

Pit-1 is a transcription factor which is expressed in the somatotrope, lactotrope, and thyrotrope cell population of the anterior pituitary gland from early fetal development throughout life. Mutations in the Pit-1 gene result in insufficient expression of this factor, accounting for a form of combined pituitary hormone deficiency for growth hormone (GH), prolactin, and thyroid-stimulating hormone. Clinical presentation at diagnosis can be variable, although all forms finally result in severe growth retardation due to GH deficiency and hypothyroidism. The clinical variability is due to other factors than the exact location of the mutation; however, the type of inheritance seems to correlate well with the genotype. Early detection of Pit-1 abnormalities might prevent the sequelae associated with some early and severe presentations of this disorder.

Kallmann syndrome in a boy with a t(1;10) translocation detected by reverse chromosome painting

Prometaphase chromosomes from a 16 year old boy with hypogonadotrophic hypogonadism and anosmia (Kallmann syndrome) showed a tiny chromosome fragment attached to the long arm of one chromosome 1 without a visible reciprocal translocation chromosome. Chromosome painting with libraries from chromosomes 1 and X excluded a t(X;1) translocation, but failed to detect a second translocation chromosome. Through reverse chromosome painting, an unbalanced der(1), t(1;10) (q44;q26) translocation could be detected. This is the third case of Kallmann syndrome with a de novo rearrangement between two autosomes. The distal long arm of chromosome 1 may contain a candidate locus for a gene, mutations of which may cause the Kallmann phenotype; a 10q location seems less likely.

Pericardial effusion as a sign of acquired hypothyroidism in children with Down syndrome

In three children with Down syndrome and acquired hypothyroidism echocardiography was performed before and after the start of L-thyroxine treatment. Initial studies revealed pericardial effusions which resolved during treatment suggesting that they were caused by hypothyroidism. The incidence of hypothyroidism in Down syndrome is high, but the diagnosis is often missed for lack of specific clinical criteria. The finding of pericardial effusion by echocardiography may be essential in discovering thyroid dysfunction. The cases illustrate that regular thyroid function tests are important in Down syndrome.

Short stature: a common feature in Duchenne muscular dystrophy

In a retrospective growth evaluation, which included parental height, birth length and a longitudinal analysis of growth and bone maturation, it has been shown that short stature is a common finding in Duchenne muscular dystrophy already in an early or even preclinical stage. Normal length and weight at birth, slow subsequent growth with a curve crossing the centiles in the 1st years of life, and normal bone maturation are characteristic of this type of short stature.

Treatment of pubertal gynaecomastia with testolactone

22 Boys with pubertal gynaecomastia (age 15.9 +/- 1.9 years) were treated with testolactone (450 mg daily by mouth) for 2 to 6 months without side-effects. The mean breast gland diameter regressed from 4.4 to 3.3, 3.2 cm, and 1.7 cm at 2, 4, and 6 months, while pubic hair and testicular volume progressed normally. Plasma androstenedione increased from 5.4 to 73.1 nmol/l. Testosterone, DHEA, and oestrone increased less, and oestradiol remained unchanged. Androgen/oestrogen ratios increased (most marked change: androstenedione/oestrone from 15 to 140). LH (basal and maximum after LHRH) did not change, but FSH increased somewhat (basal 133 to 173, maximum 225 to 269 micrograms/l). Prolactin remained unchanged. It is concluded that testolactone, an inhibitor of steroid aromatization, is an effective and safe medical treatment for pubertal gynaecomastia.

Influence of oestrogen in high and low doses on plasma steroid concentrations in girls with tall stature and Turner syndrome

Plasma DHA, 17-OH-progesterone, androstenedione, testosterone, cortisol, oestrone and oestradiol were determined before and on high dose oestrogen treatment (1, 3, 6 and 16 months) given to excessively tall girls to reduce future adult height. Basal values were normal: DHA 16.4 +/- 0.8 nmol/l (n = 90), 17-OH-progesterone 4.9 +/- 0.3 (n = 20), androstenedione 5.6 +/- 0.3 (n = 25), testosterone 2.6 +/- 0.3 (n = 24) and cortisol 395 +/- 20 (n = 90). On treatment, DHA, 17-OH-progesterone and androstenedione decreased to a minimum of 9.3 +/- 1.0 nmol/l (3 months, n = 13), 2.4 +/- 0.3 (6 months, n = 7) and 2.6 +/- 0.2 (6 months, n = 9), respectively, while testosterone remained unchanged, and cortisol increased to a maximum of 825 +/- 99 nmol/l (16 months, n = 23). In 15 girls with XO gonadal dysgenesis, basal DHA was low (11.8 +/- 1.0 nmol/l), and did not significantly change on low dose oestrogen replacement (13.3 +/- 1.4). The cause of the fall in plasma concentrations of androstenedione, DHA and 17-OH-progesterone in treated tall girls is unknown, but it is speculated that it might be related to peripheral conversion in the augmented adipose tissue mass. The rise in plasma cortisol, on the other hand, is probably due to increased transcortin.