Mortality in children with classic congenital adrenal hyperplasia and 21-hydroxylase deficiency (CAH) in Germany.

BACKGROUND: Adrenal crises in children with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) are life-threatening and have the potential to death. METHODS: A survey was performed among Paediatric Endocrinologists in Germany to report on deceased children with CAH. Our survey covered the whole of Germany. RESULTS: The participating centres reported 14 cases of death (9 female, 5 male) from 1973 until 2004, but no deaths thereafter. 11 children had the SW form and 3 the simple virilizing (SV) form. All patients were on glucocorticoid replacement, and the SW forms additionally on mineralocorticoid replacement. The age at death varied between 6 weeks and 16.5 years. Seven children died before introduction of general neonatal screening, and 7 children thereafter. Before death, the clinical signs of impending crisis were nonspecific. Five patients developed hypoglycaemia and convulsions with cerebral oedema. Half of the deceased patients died at home. The hydrocortisone dosage was only doubled in two of the 14 cases. CONCLUSIONS: According to the assessments by the attending centres, almost all deaths could be related to an inadequate administration of stress doses of hydrocortisone. Since no deceased CAH children were reported in Germany from 2005 on, we assume the effectiveness of educational programs over the past years.

Growth Hormone Treatment in Children With Prader-Willi Syndrome: Three Years of Longitudinal Data in Prepubertal Children and Adult Height Data From the KIGS Database.

Context: Longitudinal data of children with Prader-Willi syndrome (PWS) treated with genotropin were registered in the Pfizer International Growth Database (KIGS). Objective: To evaluate efficacy and safety of growth hormone (GH) treatment in a large group of children with PWS. Design: Data registered in KIGS from 1987 to 2012. Setting: Worldwide retrospective cohort study. Patients: Patients included 522 prepubertal children treated with GH for three years and 173 children who had reached adult height. Safety analysis included 2332 children. Intervention involved GH treatment. Main outcome measure: Height standard deviation score (SDS), body mass index (BMI) SDS, occurrence of serious adverse events, and deaths reported in KIGS. Results: In prepubertal children, mean (standard deviation) height SDS improved to -0.31 (1.34) (P < 0.05) during three years of GH treatment. In the adolescent group, height SDS improved until the start of puberty to -0.22 (1.31) (P < 0.05) but had a loss of -0.77 (0.81) during puberty, resulting in a mean adult height SDS of -1.19 (1.37). Total height gain was 0.95 (1.32) SDS. BMI SDS increased in the prepubertal group from 1.11 (2.09) to 1.53 (1.43) (P < 0.05) and did not significantly change in the adolescent group, who had a BMI SDS at an adult height of 1.78 (1.26). KIGS contained 12 death reports. Conclusions: GH treatment in children with PWS significantly improves linear growth. BMI remains on average below +2 SDS, in contrast to the natural course of increasing obesity in PWS. Safety should be closely monitored in children with PWS, with and without GH treatment.

Patients with Silver-Russell-Syndrome from Birth to Adulthood: Diagnosis, Development and Medical Care.

Silver-Russell syndrome (SRS) is a rare congenital disorder, characterized by a wide spectrum of signs and symptoms, which vary significantly between affected individuals. The understanding of the genetic basis of the phenotype has advanced greatly during the past decades. Together with the typical clinical picture intrauterine growth retardation and severe short stature are the key features. Failure to thrive in conjunction with frequent feeding problems in infancy and early childhood are a major challenge for the parents. In parallel to the genetic research, medical care of these children improved dramatically, and this article describes the most important issues. Treatment of short stature with rhGH as part of the approved SGA indication is able to improve growth and final height in these children. This article reviews some of the major aspects related to some of these issues.

Schoolchildren born VLBW or VLGA show height-related changes in body composition and muscle function but no evidence of metabolic syndrome risk factors. Results from the NEOLONG study.

BACKGROUND: Children born small for gestational age (SGA) are at risk for the metabolic syndrome (MetS) as adults. We examined whether indicators of MetS could be identified in pre-pubertal children born very preterm. METHODS: Parameters associated with MetS were studied in 141 pre-pubertal schoolchildren with either very low birth weight (VLBW) or GA <32 weeks (SGA: n=43). RESULTS: At 8.3±0.8 years, 36 children (SGA: n=15) were classified short. There were no differences between the SGA and appropriate for age (AGA) groups; nor were dissimilarities observed between short children and those with normal height for parameters such as body mass index (BMI), serum levels of hormones, HDL cholesterol, triglycerides, glucose, insulin, HOMA-IR, body composition, resting energy expenditure, grip strength and jump force. CONCLUSIONS: Neither SGA at birth nor short stature at follow-up (irrespective of size at birth), could be associated with parameters that indicate an increased risk for the MetS during childhood.

A 2-year multicentre, open-label, randomized, controlled study of growth hormone (Genotropin®) treatment in very young children born small for gestational age: Early Growth and Neurodevelopment (EGN) Study.

OBJECTIVE: In Europe, growth hormone (GH) treatment for children born small for gestational age (SGA) can only be initiated after 4 years of age. However, younger age at treatment initiation is a predictor of favourable response. To assess the effect of GH treatment on early growth and cognitive functioning in very young (<30 months), short-stature children born SGA. DESIGN: A 2-year, randomized controlled, multicentre study (NCT00627523; EGN study), in which patients received either GH treatment or no treatment for 24 months. PATIENTS: Children aged 19-29 months diagnosed as SGA at birth, and for whom sufficient early growth data were available, were eligible. Patients were randomized (1:1) to GH treatment (Genotropin®, Pfizer Inc.) at a dose of 0·035 mg/kg/day by subcutaneous injection, or no treatment. MEASUREMENTS: The primary objective was to assess the change from baseline in height standard deviation score (SDS) after 24 months of GH treatment. RESULTS: Change from baseline in height SDS was significantly greater in the GH treatment vs control group at both month 12 (1·03 vs 0·14) and month 24 (1·63 vs 0·43; both P < 0·001). Growth velocity SDS was significantly higher in the GH treatment vs control group at 12 months (P < 0·001), but not at 24 months. There was no significant difference in mental or psychomotor development indices between the two groups. CONCLUSIONS: GH treatment for 24 months in very young short-stature children born SGA resulted in a significant increase in height SDS compared with no treatment.

Three-year growth response to growth hormone treatment in very young children born small for gestational age-data from KIGS.

CONTEXT: Children born small for gestational age (SGA) with poor growth during the first years of life may remain short in stature during childhood and as adults. OBJECTIVE: To evaluate the 3-year growth response to GH treatment in very young short children born SGA, and to test the existing predictions models for growth response developed for older SGA children. SETTING: KIGS (The Pfizer International Growth Database). PATIENTS: A total of 620 SGA children (birth length and/or weight below -2 SD score [SDS]) on GH treatment, 156 in the 2- to 4-year-old group (100 boys; median age, 3.3 y), and 464 in the 4- to 6-year-old group (284 boys; median age, 4.9 y). RESULTS: Median values and 10th-90th percentiles are presented. Both groups presented a significant increase in height velocity during GH treatment. Median height SDS increased from -3.9 (-5.4 to -2.9) at the start to -2.2 (-3.8 to -1.0) at 3 years in the 2- to 4-year-old group (P < .01) and from -3.4 (-4.5 to -2.6) to -2.0 (-3.3 to -0.9) in the 4- to 6-year-old group (P < .01). Median weight SDS increased from -3.8 (-5.9 to -2.4) to -2.1 (-4.1 to -0.5) in the 2- to 4-year-old group (P < .01). Respective values for the 4- to 6-year-old group were -3.1 (-4.8 to -1.8) to -1.6 (-3.1 to -0.1) SDS (P < .01). First- and second-year growth response could be estimated by the SGA model. CONCLUSION: Very young children born SGA without spontaneous catch-up growth presented a significant improvement in height and weight during the 3 years of GH treatment. Growth response could be estimated by the SGA model.

Results from an international multicenter trial evaluating the ease-of-use of and preference for a newly developed disposable injection pen for the treatment of growth hormone deficiency in treatment-naïve children and adults.

Previous research has reported that ease of use of and preference for a delivery device are associated with greater patient compliance - an important factor in achieving optimal therapeutic results. The objective of this study was to assess the ease-of-use of a new disposable pen (GoQuick(®), Pfizer, Inc.) versus the current reusable pen (GENOTROPIN Pen(®), Pfizer, Inc.) to inject a daily dose of recombinant DNA origin human growth hormone, Genotropin(®) (somatropin) in standard practice. In this randomized, crossover, multicenter, multinational, open-label study, ease-of-use of and preference for the two pens were assessed in three treatment-naïve populations: 1) parents of very young children; 2) parent-child dyads; and 3) adults via use of a validated self-report Injection Pen Assessment Questionnaire (IPAQ) after 2 months of at-home-use experience. The primary endpoint was the proportion of participants who reported the new disposable pen to be no different from or easier to use than the current reusable pen. Safety was also assessed and reported according to local legal requirements. Of the 120 screened patients, 119 were included in the ease-of-use analysis and all were included in the safety analyses. In all, 67.2% found the new somatropin disposable pen to be no different from or easier to use than the reusable pen (95% confidence interval: 58.8-75.7). Most adverse events were mild or moderate. No deaths or device- or treatment-related serious adverse events were reported. These results suggest that improvements made to the reusable somatropin pen are tangible and recognizable to treatment-naïve patients and their caregivers, child-caregiver dyads, and adults, and may positively impact continued compliance with therapy. REGISTRY INFORMATION: ClinicalTrials.gov identifier: NCT01112865.

IGF1R mutation analysis in short children with Silver-Russell syndrome features.

The insulin-like growth factor 1 receptor (IGF1R) is a key factor in intrauterine and postnatal growth by mediating the biological function of IGF-I. Mutations of IGF1R gene are usually associated with growth retardation, but the clinical picture of IGF1R mutation carriers is heterogeneous. Indeed, these patients show clinical signs compatible with Silver-Russell syndrome (SRS), and some IGF1R mutation carriers have been identified in SRS cohorts. We therefore investigated deoxyribonucleic acid samples of 19 growth-retarded patients with SRS features. Apart from 8 non-pathogenic variants, we detected heterozygosity for the unknown duplication, c.1056_1057dup, leading to a premature termination in one patient and his growth retarded sister. Due to its nature, we assumed that this variant is probably pathogenic. However, the patient and his sister exhibited spontaneous catch-up growth in later life. We therefore hypothesize that the c.1056_1057dup does not result in a significant disruption to the GH-IGFI axis. Thus, this IGF1R mutation without obvious clinical consequence might challenge the actual concept of IGF1R haploinsufficiency as a general cause for disturbed growth in IGF1R mutation carriers. In the future, mutation analysis of IGF1R should be considered in growth-retarded patients with microcephaly and minor SRS features, but not in probands with the characteristic SRS phenotype including macrocephaly.

Growth hormone treatment in short children born prematurely--data from KIGS.

CONTEXT: Children born prematurely with growth failure might benefit from GH treatment. OBJECTIVES: The aim was to evaluate the first year growth response to GH treatment in short children born prematurely and to identify predictors of the growth response. DESIGN/PATIENTS: A total of 3215 prepubertal children born prematurely who were on GH treatment were selected from KIGS (The Pfizer International Growth Database), a large observational database. They were classified according to gestational age as preterm (PT; 33 to no more than 37 wk) and very preterm (VPT; <33 wk), and according to birth weight as appropriate for gestational age [AGA; between -2 and +2 sd score (SDS)] and small for gestational age (SGA; -2 SDS or below). RESULTS: Four groups were identified: PT AGA (n = 1928), VPT AGA (n = 629), PT SGA (n = 519), and VPT SGA (n = 139). GH treatment was started at a median age of 7.5, 7.2, 6.7, and 6.0 yr, respectively. After the first year of GH treatment, all four groups presented a significant increase in weight gain and height velocity, with a median increase in height SDS higher than 0.6. Using multiple stepwise regression analysis, 27% of the variation in height velocity could be explained by the GH dose, GH peak during provocative test, weight and age at GH start, adjusted parental height, and birth weight SDS. The first year growth response of the children born PT and SGA could be estimated by the SGA model published previously. CONCLUSION: Short children born prematurely respond well to the first year of GH treatment. Long-term follow-up is needed.

Discontinuation of growth hormone (GH) treatment during the transition phase is an important factor determining the phenotype of young adults with nonidiopathic childhood-onset GH deficiency.

CONTEXT: Little is known about the impact of childhood-onset GH deficiency (GHD), in particular the duration of GH cessation during the transition phase, on adult phenotype. OBJECTIVE: We investigated the association between the manifestations and management of GHD during childhood/adolescence and the clinical features of GHD in adulthood. DESIGN/SETTING/PATIENTS/INTERVENTION: Patients with reconfirmed childhood-onset GHD who resumed GH treatment as adults were identified from two sequential databases (n = 313). The cohort was followed up longitudinally from GH start in childhood to reinitiation of treatment in adulthood and 1 yr beyond. Analyses were performed in the total cohort and in subgroups of patients with idiopathic GHD (IGHD) and non-IGHD. The cohorts were stratified based on duration of GH cessation (short, < or = 2 yr; long, > 2 yr). MAIN OUTCOME MEASURES: Regimen of pediatric GH administration, duration of GH interruption, IGF-I sd score, lipid concentrations, and quality of life were measured. RESULTS: Mean duration of GH interruption was 4.4 yr. IGF-I sd score in adulthood was related to severity of childhood GHD. In non-IGHD patients, a longer duration of GH interruption was associated with a worse lipid profile (P < 0.0001). Non-IGHD patients who gained more height during childhood GH treatment reported better quality of life than those who gained less height (P < 0.05). CONCLUSIONS: Pediatricians should tailor GH treatment, not only for its beneficial effect on growth but also for future health in adulthood. In adults with reconfirmed GHD, particularly those with non-IGHD, early recommencement of GH should be considered.

LOT1 (ZAC1/PLAGL1) as member of an imprinted gene network does not harbor Silver-Russell specific variants.

Silver-Russell syndrome (SRS) is a heterogeneous disease associated with intrauterine and postnatal growth retardation (IUGR/PNGR), asymmetry and craniofacial dysmorphisms. In 7-10% of patients with SRS, maternal uniparental disomy of chromosome 7 can be detected; more than 38% carry hypomethylation of the imprinting region 1 in 11p15. These chromosomes harbor the imprinted genes IGF2, H19, LIT1 and MEST. In mice, interaction of these genes with the prenatally rexpressed Plagl1/Zac1 has been reported. The aim of this study was to identify mutations in the maternally imprinted LOT1(ZAC1/PLAGL1) gene in 6q24 in patients with SRS. We screened 30 patients with SRS and 14 patients with isolated IUGR/PNGR by SSCP and/or direct sequencing. Mutation analysis revealed nine genomic variants. Seven were novel but classified as apathogenic. Interestingly, two of these variants, g.10212T/A and g.10214C/A, showed strict association. However, our results do not indicate a relevant role of mutations in LOT1(ZAC1/PLAGL1) in the etiology of SRS.

No evidence for isolated imprinting mutations in the PEG1/MEST locus in Silver-Russell patients.

Imprinting defects have meanwhile been described in nearly all human imprinting disorders among them Silver-Russell syndrome (SRS). In this disorder, 11p15 epimutations and maternal Uniparental Disomy of chromosome 7 (UPD7) are detectable in approximately 50% of patients. To find out whether isolated imprinting defects on chromosome 7 play a role in the aetiology of SRS we screened a cohort of 54 SRS patients without 11p15 epimutations. Methylation-specific PCR was carried out for the PEG1/MEST locus in 7q31. This test detects all known segmental and complete UPD7 cases. The exclusion of isolated imprinting defects in our study population shows that this type of epimutation at the PEG1/MEST locus in 7q31 does not play a relevant role in SRS. However, the role of imprinting disturbances in other genes cannot be excluded.

Search for subtelomeric imbalances by multiplex ligation-dependent probe amplification in Silver-Russell syndrome.

Chromosomal aberrations are typically associated with primordial growth retardation, psychomotoric constrictions, and dysmorphisms. Since these features may be present in patients with Silver-Russell syndrome (SRS) and chromosomal disturbances are also detected in a subgroup of SRS patients, we screened a cohort of 45 SRS patients for cryptic subtelomeric imbalances. Submicroscopic deletions/duplications in the telomere regions are meanwhile well known to cause a broad spectrum of conspicuous phenotypes, characterized by mental retardation and multiple further congenital anomalies. We hypothesize that SRS might represent at the mild end of the broad phenotypic range of subtelomeric imbalances. Screening of the patients was performed by multiplex ligation-dependent probe amplification (MLPA), a technique that has already been shown to be effective and reliable for measuring copy numbers. We excluded pathogenetically relevant copy number variations in the subtelomeres in our SRS patient cohort, but one patient carried an apathogenic polymorphic Yq deletion. It can therefore be concluded that this type of chromosomal aberration does not belong to the genetic causes of SRS and it is not necessary to include this test in the diagnostic algorithm of the disease.

The endocrine phenotype in silver-russell syndrome is defined by the underlying epigenetic alteration.

CONTEXT: Around 50% of children with Silver-Russell syndrome (SRS) carry a hypomethylation of the imprinting control region 1 at the IGF2/H19 locus on 11p15, the functional significance of which is unknown. OBJECTIVE: We aimed to compare the genotype in SRS with the endocrine phenotype. DESIGN: The retrospective study included all SRS children who were treated during the last 18 yr at our hospital and for comparison a cohort of GH treated nonsyndromic short children born small for gestational age (SGA). PATIENTS: The 61 patients with SRS included were defined by the presence of intrauterine growth retardation, lack of catch-up growth, and at least two of the criteria: typical face, relative macrocephaly, and skeletal asymmetry. Routine karyotype and GH secretion was normal in all children studied. A subgroup of 53 patients was treated with GH. MATERIALS AND METHODS: Genomic DNA was available from 44 children. Multiplex ligation probe-dependent amplification analysis was performed to detect hypomethylation at the imprinting control region 1 on 11p15. Uniparental disomy of chromosome 7 (UPD7) was analyzed by short tandem repeats typing. Serum levels of GH, IGF-I, and IGF-binding protein (IGFBP)-3 were measured by RIA. RESULTS: Epimutations at 11p15 were found in 19 of 44, UPD7 in five of 44, and small structural aberrations of the short arm of chromosome 11 in two of 44 children. Of 44 cases, 18 were negative for any genetic defect known (41%). The most severe phenotype was found in children with 11p15-SRS. Children with UPD7-SRS had a significantly higher birth length (P < 0.004) but lost height sd score (SDS) postpartum, whereas children with 11p15-SRS showed no change in height SDS. IGF-I and IGFBP-3 serum levels were inadequately high in 11p15-SRS at -0.02 SDS (1.07, sd) and +1.38 SDS (1.01), compared with the low levels in UPD7-SRS and in the cohort of 58 nonsyndromic SGA children (P < 0.0009). During GH therapy, IGFBP-3 serum levels increased above normal values in 11p15-SRS (P < 10(-4)), whereas IGF-I increase was moderate. There was a trend toward more height gain in children with UPD7 than in those with 11p15 epimutation under GH therapy (+2.5 vs. +1.9 height SDS after 3 yr) (P = 0.08). CONCLUSIONS: Children with SRS and an 11p15 epimutation have IGFBP-3 excess and show endocrine characteristics suggesting IGF-I insensitivity, whereas children with SRS and UPD7 were not different from nonsyndromic short children born SGA. This phenotype-genotype correlation implicates divergent endocrine mechanisms of growth failure in SRS.

Are H19 variants associated with Silver-Russell syndrome?

Opposite (epi)mutations affecting the imprinted region 11p15 are associated with Silver-Russell (SRS) and Beckwith-Wiedemann syndrome (BWS). Apart from other disturbances more than 35% of patients with SRS show hypomethylation at the imprinting control region 1 (ICR1) in 11p15. ICR1 is paternally methylated and regulates the expression of the paternally expressed growth factor IGF2 and the maternally expressed gene H19. The exact function of the non-coding RNA H19 is still unknown. However, the finding that this gene is highly conserved in mammals indicates profound functional relevance. Due to the supposed function of H19 in the regulation of the imprinted region 11p15 we searched for mutations in the transcribed sequence and the CTCF binding sites of H19 in 44 patients with SRS. In two cases different 3 base-pair (bp) deletions in exon 1 could be identified. A third patient carried a 39 bp duplication affecting exon 2 and intron 2. These three variants were not detected in 100 controls and 42 patients with isolated growth retardation. One of the patients carrying a mutation also showed hypomethylation at the ICR1 in 11p15. Splicing studies in HEK cells transfected with constructs carrying the three different variants revealed a deviation from the normal H19 splicing pattern in two of these individuals. However, analysis of lymphocytes of one of these two patients did not verify an altered expression pattern of H19. Nevertheless, our results indicate a relevant role of H19 in the aetiology of SRS: functional effects of these variants on chromatin restructuring of the ICR1, or altered function of H19 as a posttranslational modifying factor (microRNA/antisense RNA) are conceivable.

Growth and development are similar in VLBW children born appropriate and small for gestational age: an interim report on 97 preschool children.

AIM: To investigate growth and development in a cohort of children born with very low birth weight (VLBW) treated at a single tertiary neonatal unit. METHODS: We studied 97 children born between January 1995 and July 1997 with BW <1,500 g. At follow-up (mean age 3.7 years) anthropometric data and data on neurological status, motor, speech and language development were collected. Small for gestational age (SGA) was defined as weight and/or length at birth <10th percentile; shortness at follow-up was defined as height <10th percentile. RESULTS: Comparison was made between the appropriate for gestational age (AGA) (n = 46) and SGA (n = 51) groups. At follow-up, 23 AGA and 35 SGA children were short, had a smaller head circumference (-1.9 vs -0.8 SDS), were lighter at birth (BW -1.3 vs -0.7 SDS), and had a higher rate of broncho-pulmonary dysplasia (BPD) (28 vs 12); no differences in neonatal characteristics or neurological status were evident. A higher frequency of motor delay occurred in the 'short' group. Short children also had a smaller head circumference (HC) (-1.6 vs -0.7). Short SGA children had a higher frequency of BPD, smaller HC (-2.1 vs -1.0), and a slightly higher proportion of suspicious neurological findings, motor delay, and speech and language delay (n.s.). CONCLUSIONS: Preterm VLBW infants, whether AGA or SGA at birth, face the risk of being short at preschool age. Height outcome is probably influenced by postnatal factors. Our data also suggest that short stature is associated with developmental difficulties in this population.

Major determinants of height development in Turner syndrome (TS) patients treated with GH: analysis of 987 patients from KIGS.

Little is known about factors determining height outcome during GH treatment in Turner syndrome (TS). We investigated 987 TS children within the Kabi International Growth Study (KIGS) who had reached near adult height (NAH) after >4 y GH treatment (including >1 y before puberty). Through multiple regression analysis we developed a model for NAH and total gain. Our results were as follows (median): 1) At start, age 9.7 yrs, height (HT) 118.0 cm (0.0 TS SDS), projected adult height 146.1 cm, GH dose 0.27 mg/kg wk; 2) NAH HT 151.0 cm (1.5 TS SDS); 3) Prepubertal gain 21.2 cm (1.6 TS SDS); 4) Pubertal gain 9.4 cm (0.0 TS SDS). NAH correlated (r = 0.67) with (ranked) HT at GH start (+), 1 year responsiveness to GH (+), MPH (+), age at puberty onset (+), age at GH start (-), and dose (+). The same factors explained (R = 0.90) the total HT gain. However, HT at GH start correlated negatively. Karyotype had no influence on outcome. Evidently, height at GH start (the taller, the better), age at GH start (the younger, the better), the responsiveness to GH (the higher, the better) and age at puberty (the later, the better) determine NAH.

No evidence for additional imprinting defects in Silver-Russell syndrome patients with maternal uniparental disomy 7 or 11p15 epimutation.

Silver-Russell syndrome (SRS) is mainly characterised by intrauterine and postnatal growth retardation (IUGR and PNGR), asymmetry, clinodactyly V and craniofacial abnormalities. More than 35% of patients carry a hypomethylation of the telomeric imprinting centre region 1 (ICR1) in 11p15; single patients show a maternal duplication of 11p15. An additional 7-10% of patients with SRS have maternal uniparental disomy of chromosome 7 (mUPD7). Another disorder caused by epigenetic defects is transient neonatal diabetes mellitus (TNDM) which is associated with loss of methylation (LOM) in 6q24. After detecting methylation loss at multiple imprinted loci in patients with TNDM, Mackay et al. recently proposed the existence of a maternal hypomethylation syndrome presenting as TNDM. They therefore concluded that patients with other disorders associated with LOM at one (maternally) methylated locus might also carry LOM at multiple loci. Similar observations have also been reported in Beckwith-Wiedemann syndrome (BWS): nearly 25% of patients displayed abnormal methylation patterns of ICRs additional to those in 11p15. To show whether general hypomethylation is a common phenomenon in imprinting disorders we carried out methylation analyses for the imprinted regions 14q32, 6q24 and the centromeric imprinting region ICR2 on 11p15 for 10 patients with SRS carrying mUPD7 and 22 patients with LOM at the telomeric imprinting region ICR1. We showed that further epigenetic defects did not occur in the groups of SRS with LOM of ICR1 or mUPD7, and that these subentities do not belong to the diseases with a general hypomethylation defect, such as TNDM and BWS.

The centromeric 11p15 imprinting centre is also involved in Silver-Russell syndrome.

Silver-Russell syndrome (SRS) is a heterogeneous disorder characterised by severe intrauterine and postnatal growth retardation, limb and body asymmetry, a typical facial appearance and less common dysmorphisms. Recently, epimutations and maternal duplications affecting the short arm of chromosome 11 have been shown to have a crucial role in the aetiology of the disease. Disturbances in the same genomic region cause the overgrowth disorder Beckwith-Wiedemann syndrome (BWS). In BWS, mutations in the telomeric as well as in the centromeric imprinting centres (ICR1 and ICR2) in 11p15 can be observed. In SRS, methylation defects in the imprinted region in 11p15 were considered to be restricted to the telomeric ICR1. They can be detected in about 30% of patients. This article reports on the first patient with SRS with a cryptic duplication restricted to the centromeric ICR2 domain in 11p15. The maternally inherited duplication in this patient included a region of 0.76-1 Mbp and affected the genes regulated by the ICR2, among them CDKN1C and LIT1. This study provides evidence for a role for this imprinting centre in the aetiology of SRS and shows that SRS presents a picture genetically opposite to that of BWS.