Reevaluation of Russell-Silver syndrome

Behavioural abnormalities in a novel mouse model for Silver Russell Syndrome

Silver Russell Syndrome (SRS) syndrome is an imprinting disorder involving low birth weight with complex genetics and diagnostics. Some rare SRS patients carry maternally inherited microduplications spanning the imprinted genes CDKN1C, PHLDA2, SLC22A18 and KCNQ1, suggesting that overexpression of one of more of these genes contributes to the SRS phenotype. While this molecular alteration is very rare, feeding difficulties are a very common feature of this condition. Given that SRS children also have very low body mass index, understanding the underpinning biology of the eating disorder is important, as well as potential co-occurring behavioural alterations. Here, we report that a mouse model of this microduplication exhibits a number of behavioural deficits. The mice had a blunted perception of the palatability of a given foodstuff. This perception may underpin the fussiness with food. We additionally report hypoactivity, unrelated to anxiety or motoric function, and a deficit in the appropriate integration of incoming sensory information. Importantly, using a second genetic model, we were able to attribute all altered behaviours to elevated expression of a single gene, Cdkn1c. This is the first report linking elevated Cdkn1c to altered behaviour in mice. Importantly, the findings from our study may have relevance for SRS and highlight a potentially underreported aspect of this disorder.

Quantitative analysis of methylation status at 11p15 and 7q21 for the genetic diagnosis of Beckwith-Wiedemann syndrome and Silver-Russell syndrome

Methylation-specific (MS) multiplex ligation-dependent probe amplification (MLPA) at two differentially methylated regions (DMRs) at chromosome 11p15, H19-DMR and LIT1-DMR, and microsatellite analysis for uniparental disomy (UPD) at chromosome 7 or 11, have been recommended for the genetic diagnosis of the Beckwith-Wiedemann syndrome (BWS) and the Silver-Russell syndrome (SRS). In this study, the efficacy of the MS pyrosequencing method at H19-DMR and LIT1-DMR at 11p15 and SGCE-DMR at 7q21 was evaluated for the genetic diagnosis of BWS (n=18) and SRS (n=20) patients. Epigenetic alterations or UPD were detected in 83% of BWS and 50% of SRS individuals by MS-MLPA, but the detection rate increased to 95% of BWS and 70% of SRS by MS pyrosequencing. Thirteen BWS patients (72%) harbored loss-of-methylation (LOM) at LIT1-DMR and two patients (11%) harbored gain-of-methylation (GOM) at H19-DMR, whereas two patients (11%) had both LOM at LIT1-DMR and GOM at H19-DMR, reflecting paternal UPD 11. Thirteen SRS patients (65%) harbored LOM at H19-DMR, whereas one patient (5%) had GOM at SGCE-DMR, reflecting maternal UPD 7. Birth anthropometric profiles were significantly correlated to methylation scores at either H19-DMR or LIT1-DMR. In conclusion, MS pyrosequencing enhanced the detection rate of molecular defects in BWS and SRS. Moreover, it indicates that methylation status at 11p15.5 might have an important role in fetal growth.

Is autosomal recessive Silver-Russel syndrome a separate entity or is it part of the 3-M syndrome spectrum?

Intrauterine growth retardation (IUGR) is a nonspecific finding that occurs in approximately 0.17% of all live-births. However, IUGR can also be a significant feature of many recognized genetic syndromes including Silver-Russel syndrome (SRS), Three M syndrome (3-M), Dubowitz syndrome, and Mulibrey nanism. Differentiation of 3-M syndrome from autosomal recessive SRS has been difficult because of the phenotypic variability of the latter. Limb length asymmetry is seen in over half of those with autosomal recessive SRS, but not in individuals with 3-M syndrome. Characteristic radiologic findings of 3-M syndrome are not present in SRS. We used single nucleotide polymorphism (SNP) microarrays to investigate the cause of phenotypic features of SRS that shows autosomal recessive inheritance in three consanguineous families, two from United Arab Emirates (UAE), and one from Jordan. The mapped regions contained CUL7 and OBSL1, the genes that have recently been shown to cause 3-M syndrome. Subsequently, direct DNA sequencing of CUL7 and OBSL1 genes revealed novel mutations in both genes including two mutations in OBSL1 [c.1119G>C (p.W373C) and c.681_682delinsTT (p.Q228X)], and a nonsense mutation in CUL7 [c.203G>A (p.W68X)]. In addition, a six nucleotide deletion in CUL7 [c.649_654delAGCCGC (p.217_218delSR)] was found in a consanguineous family from UAE that had the typical features of 3-M. As a result of these findings, we question the identity of the autosomal recessive SRS and suggest that all apparently recessive SRS families should be tested for mutations in CUL7 and OBSL1.

IGF-I and IGF Binding Protein-3 Generation Tests and Response to Growth Hormone in Children with Silver-Russell Syndrome

Objectives. To evaluate, in children with Silver-Russell Syndrome, the response to the IGF-I and IGFBP-3 generation test and compare results to the growth response after 6 months of rhGH. Methods. Eight children (6 males), with a mean age of 5.71 ± 2.48 years and height SDS of -3.88 ± 1.28 received rhGH for 6 months. IGF-I and IGFBP-3 were analyzed before and after 4 doses of rhGH. Results. The mean growth velocity (GV) before treatment was 5.28 ± 1.9 cm/year. GV increased after rhGH in five children to a mean GV of 10.3 ± 3.64 cm/year. Six children had normal basal IGF-I levels and two low levels. After 4 doses of rhGH, the IGF-I levels were normal in seven. There was no correlation between the growth response and the IGF-I generation test. Conclusions. Children with SRS have normal IGF-I generation test. There is no correlation between the generation test and the growth velocity after 6 months of rhGH.

Intrauterine growth retardation associated with precocious puberty and sertoli cell hyperplasia

The original description of patients with Russell-Silver syndrome included precocious puberty, the mechanism of which was unclear. We describe a child with a Russell-Silver syndrome-like phenotype who presented with precocious puberty that was associated with hyperplasia of the Sertoli cells. The patient was found to have an immature cryptorchid testicle; hyperplastic Sertoli cells were also aneuploid carrying trisomy 8. This chromosomal abnormality was present in Sertoli cells only and could not be detected in peripheral lymphocytes, tunica vaginalis, or other, normal, testicular tissue. Sertoli cells in culture showed excess aromatization providing an explanation for the rapid advancement of the patient's bone age. We conclude that in a patient with a Russell-Silver syndrome-like phenotype, Sertoli cell hyperplasia was associated with somatic trisomy 8, increased aromatization, and gonadotropin-independent precocious puberty.

Clinically distinct epigenetic subgroups in Silver-Russell syndrome: the degree of H19 hypomethylation associates with phenotype severity and genital and skeletal anomalies

CONTEXT

The H19 imprinting control region (ICR), located on chromosome 11p15.5, has been reported hypomethylated in 20-65% of Silver-Russell syndrome (SRS) patients.

OBJECTIVE

We investigated the methylation status of 11p15.5 ICRs in SRS patients and children born small for gestational age (SGA) to clarify the relationship between phenotype and H19 methylation status.

METHODS

We performed methylation screens of the H19 and KCNQ1OT1 ICRs in 42 SRS patients, including seven maternal uniparental disomy of chromosome 7 patients, and 90 SGA children without SRS. Clinical data were evaluated from patient records, and seven hypomethylated patients were clinically and radiologically reexamined.

RESULTS

H19 ICR hypomethylation was found in 62% of SRS patients but in no SGA children. A clinical severity score demonstrated strong correlation between hypomethylation level and phenotype severity. Hypomethylation related to a more severe SRS phenotype, in which especially asymmetry and micrognathia were significantly more common. Extremely hypomethylated patients had abnormally high lumbar vertebrae, lumbar hypomobility, elbow subluxations, and distinct hand and foot anomalies. They also presented with congenital aplasia of the uterus and upper vagina, equivalent to the Mayer-Rokitansky-Küster-Hauser syndrome in females, and cryptorchidism and testicular agenesis in males.

CONCLUSIONS

We found a dose-response relationship between the degree of H19 hypomethylation and phenotype severity in SRS. We report for the first time the association of specific anomalies of the spine, elbows, hands and feet, and genital defects in SRS with severe H19 hypomethylation. Classical SRS features were found in H19 hypomethylation and milder symptoms in maternal uniparental disomy of chromosome 7, thus distinguishing two separate clinical and etiological subgroups.

Silver-russell syndrome: a case report

A 15-year-old male boy with hemihypertrophy (left side) of the body was admitted in the hospital with the history of repeated attacks of convulsion. The patient was diagnosed as Silver-Russell syndrome on clinical ground. Silver-Russell syndrome (SRS) is a very rare genetic disorder that appears no later than early childhood. This is usually characterized by asymmetry in the size of the two halves or other parts of the body. Silver-Russell Syndrome occurs mostly in isolated cases because of sporadic genetic changes (mutations) for no apparent reason. For lack of facilities we were not able to do genetic study.

Musculoskeletal manifestations of Russell-Silver syndrome

The musculoskeletal manifestations of Russell-Silver syndrome were studied in 25 patients. The most common manifestations were short stature (25 patients), limb-length discrepancy (23 patients), clinodactyly (19 patients) metacarpal bone and phalangeal abnormalities (13 patients), scoliosis (9 patients), foot syndactylism (5 patients), and developmental dysplasia of the hips (3 patients). Five patients underwent lower extremity limb-lengthening procedures for discrepancies greater than 3 cm and three patients had successful pelvic and/or femoral osteotomies for hip dysplasia. All 18 patients studied had retardation of bone age, which peaked at age 7 years.

Bilateral reactive lymphoid hyperplasia of the orbit in a child with Russell-Silver syndrome

Russell-Silver syndrome (RSS) primarily includes intrauterine growth retardation, postnatal growth failure, body asymmetry, and craniofacial disproportion. Four types of malignancies have been reported in patients with RSS: craniopharyngioma, testicular seminoma, hepatocellular carcinoma, and Wilms tumor.

The Russell-Silver syndrome: a case report and brief review of the literature

The Russell-Silver syndrome's phenotypic features consist of musculoskeletal abnormalities, genitourinary malformations, craniofacial dysmorphy and cutaneous dyschromia, which is usually reported as café au lait spots. We present the first instances of a large, unilateral, achromic patch as an additional cutaneous manifestation of the Russell-Silver syndrome.

Distraction osteogenesis in Silver Russell syndrome to expand the mandible

Distraction osteogenesis is a method commonly used to activate bone regeneration in nonunions and osseous defects and for lengthening procedures of tubular bones. This technique involves the sectioning of a bone and the subsequent deliberate, controlled movement of the opposing sectioned edges to lengthen, widen, or reposition a bone, or all three. In this report, a patient with Silver Russell syndrome and severe mandibular hypoplasia was treated by means of distraction osteogenesis of the midsymphysis to widen the mandible in concert with sagittal-ramus osteotomies to lengthen the mandible. This treatment created significantly increased arch length in the mandible, which was necessary to facilitate the patient's orthodontic treatment. We believe this is the first reported case of distraction osteogenesis to widen the mandible with the use of a tooth-borne appliance.

Human PEG1/MEST, an imprinted gene on chromosome 7

The mouse Peg1/Mest gene is an imprinted gene that is expressed particularly in mesodermal tissues in early embryonic stages. It was the most abundant imprinted gene among eight paternally expressed genes (Peg 1-8) isolated by a subtraction-hybridization method from a mouse embryonal cDNA library. It has been mapped to proximal mouse chromosome 6, maternal duplication of which causes early embryonic lethality. The human chromosomal region that shares syntenic homology with this is 7q21-qter, and human maternal uniparental disomy 7 (UPD 7) causes apparent growth deficiency and slight morphological abnormalities. Therefore, at least one paternally expressed imprinted gene seems to be present in this region. In this report, we demonstrate that human PEG1/MEST is an imprinted gene expressed from a paternal allele and located on chromosome 7q31-34, near D7S649. It is the first imprinted gene mapped to human chromosome 7 and a candidate for a gene responsible for primordial growth retardation including Silver-Russell syndrome (SRS).

A longitudinal study of early intellectual development in hemiplegic children

Thirty-eight 3- to 5-year-old children with unilateral lesions sustained pre- or peri-natally were studied longitudinally over a 2-year period, and their IQ scores compared with those of 20 "medical' controls. The failure to discover laterality effects following early unilateral injury supports the hypothesis of at least broad functional equipotentiality. There were few decrements in intellectual functioning provided the injury was not accompanied by seizures. The presence of seizures in contrast had a deleterious effect on both verbal and nonverbal aspects of cognitive functioning. While the IQs of the hemiplegic groups showed considerable stability over the 2-year span of the study, there was evidence that performance IQ, even in seizure-free patients, might be selectively impaired because of competition within the intact neural space for the sparing of verbal IQ.

Growth hormone therapy in Silver Russell syndrome: 5 years experience of the Australian and New Zealand Growth database (OZGROW)

Data were analysed on 33 children (22 males) with Silver Russell syndrome treated with growth hormone for periods up to 5 years. Baseline data (medians) at commencement of growth hormone (GH) therapy were age 6.7 years, bone age delay 1.7 years, height standard deviation score (SDS)-3.2, weight SDS -3.1, and growth velocity 5.7 cm/ year. All were prepubertal. Median birth weight SDS for gestational age was -3.2. GH was commenced at 14 IU/m2 per week and subsequently adjusted according to response. Growth velocity and growth velocity SDS for chronological age (CA) improved over baseline and gains in height SDS for CA were 1.0, 1.5 and 1.8 SD over 3, 4 and 5 years respectively (P < 0.001). No significant increase in height SDS for bone age was observed. Increased GH doses were required after the 1st year to maintain growth rates. Mean bone age advancement was 3.1 years after 3 years of treatment, and 6.0 years after 5 years treatment. Younger age was a predictor of the growth response over the 1st year. Predictors of response after 3 years were catch up growth, low weight SDS at birth and low height SDS for CA. Age at onset of puberty was normal, but height at onset of puberty was lower than normal means.

CONCLUSION

We have demonstrated significant improvement in growth in Silver Russell syndrome after 3 years of GH therapy, however data on estimated mature height and final height are insufficient to conclude final outcomes. Further follow up is required to assess the long-term benefit.

Growth and symptoms in Silver-Russell syndrome: review on the basis of 386 patients

The spontaneous growth of 386 patients (163 girls and 223 boys) with Silver-Russell syndrome (SRS) was analysed in a mixed longitudinal and cross-sectional manner. One hundred and twenty patients were seen in the two centres between 1970 and 1993, additional definite cases were added from the literature. Mean (+/- SD) length of full-term babies with SRS at birth was 43.1 +/- 3.7 cm (n = 102) in both sexes. Mean weight at birth was 1940 +/- 353 g in boys and 1897 +/- 325 g in girls. During the first 3 years of life there was poor growth with a further loss in height. Between ages 4 and 10 years there was constant growth in parallel to the 3rd percentile with a mean height SDS of -4.3. The pubertal growth spurt was reduced in the whole group. Bone age development paralleled growth, retardation increased during the first years, remained constant during prepubertal time and caught up in early puberty. Mean adult height was 151.2 +/- 7.8 cm in males and 139.9 +/- 9.0 cm in females. Head circumference for age was in the lower normal range (mean SDS for 156 prepubertal boys -1.8; mean SDS for 97 prepubertal girls -2.2).

CONCLUSION

Normative data on spontaneous growth of children with Silver-Russell syndrome are described, allowing a better counselling of patients as well as the judgement of the effects of growth promoting therapies.

Craniofacial and dental characteristics of Silver-Russell syndrome

We found significant differences in a craniometric, cephalometric, and dental study of 19 Silver-Russell syndrome patients (13 without growth hormone treatment) with appropriate controls. Although head circumference was normal for age, head length was increased, while cranial and facial widths and facial heights were reduced. Posterior facial height, posterior cranial base length, cranial base height, and mandibular body size were significantly smaller than in healthy children of the same height. Articulatory speech disorders were common. Enamel defects pointed to an early prenatal insult. Delayed dental age and small mandibular and cranial base dimensions support the possibility of physiological growth hormone deficiency in many Silver-Russell syndrome children; however, facial soft tissue structures were strikingly different from those observed in classical growth hormone deficiency.

Cognitive abilities associated with the Silver-Russell syndrome

There is no consensus opinion on whether or not cognitive impairments are found in the Silver-Russell syndrome. An investigation of a substantial sample was undertaken, using standardised assessments, in 20 boys and five girls aged 6.0 years to 11.8 years. Mean (SD) birth weights were -2.65 (0.95) SD scores, corrected for gestation. At evaluation the children had a mean (SD) age of 8.8 (1.8) years and a mean height of -2.26 (1.5) SD scores. Tests of cognitive abilities included assessments of general intelligence, reading and arithmetic attainments, and a cognitive processing task. Most had some degree of developmental delay: mean (SD) full scale IQ was 86 (24); 32% scored within the learning disability range (that is, IQ < 70); 40% were reading at least 24 months below their chronological age. Current head circumference correlated highly with full scale IQ. Assessments of special educational needs had been completed on 36%; 48% were receiving speech therapy. Approximately half of children with the Silver-Russell syndrome have significant impairment of their cognitive abilities.

Dwarfism with gloomy face: a new syndrome with features of 3-M syndrome

Nine children with primordial dwarfism are described and a new syndrome is delineated. The significant features of this syndrome include facial dysmorphism with gloomy face and very short stature, but no radiological abnormality or hormone deficiency. Mental development is normal. The mode of inheritance seems to be autosomal recessive because of consanguinity in three of the four sibships. Some overlap with the 3-M syndrome is discussed but the autonomy of the gloomy face syndrome seems to be real.

Three-generation dominant transmission of the Silver-Russell syndrome

We report on 7 patients with the Silver-Russell syndrome (SRS) in two 3-generation families. Three patients in each of the families had an undergrowth of the left side of the body when compared with the normal right side. The clinical courses were mild as compared to the severity sometimes described in sporadic cases. These patients and a review of 190 SRS cases from the literature showed that there were 23 families in which 38 patients had completely expressed SRS. In 17 of the families, multiple maternal relatives had complete or partial expressions of the SRS. Most SRS patients have been reported to occur sporadically; however, of the 197 propositi analyzed, 19% had more than one affected individual in a family and several different modes of inheritance could have been responsible. Two families (8.7%) had spontaneous dominant mutations (twins) and possible autosomal recessive transmission was present in 4 families (17.4%). Because no male-to-male transmission has yet been documented in the 21 families in the literature and the two families reported here, X-linked dominant inheritance is a possibility in 17 families (74%). Thus, although sporadic occurrences and genetic heterogeneity appear to be involved in the SRS, dominant inheritance may be a major causal factor.

3M dwarfism: a study of two further sibs

Two sibs are reported with clinical and radiological features of the 3M syndrome. The differential diagnosis is discussed, particularly with regard to Russell-Silver syndrome.

Severe Silver-Russell syndrome

Three children are described with severe Silver-Russell syndrome. Major medical problems occurred in the first two years of life in all three. Silver-Russell syndrome should be considered in the differential diagnosis of children with severe pre- and postnatal growth deficiency.

Growth hormone secretion and growth hormone treatment in children with intrauterine growth retardation. Swedish Paediatric Study Group for Growth Hormone Treatment

Few children with intrauterine growth retardation (IUGR) fail to show catch-up growth during the first year of life. There may be many reasons for this, ranging from disturbances of hormone production to hormonal unresponsiveness of target cells. This report presents preliminary data on growth hormone (GH) secretion and responses to GH treatment in 16 children with IUGR and poor catch-up growth, six of whom had Silver-Russell stigmata. GH secretion was assessed by measurement of the GH response to an arginine-insulin test and determination of spontaneous GH secretion over 24 hours. GH production was heterogeneous but, more often than expected, children showed both a low response to GH provocation and low spontaneous secretion of GH. Five out of six of the children with Silver-Russell syndrome and seven out of 10 of the children with non-Silver-Russell IUGR gained more than 2 cm in height during 1 year of treatment with GH at a dose of 0.1 IU/kg/day. These results clearly demonstrate that some children with IUGR and poor catch-up growth secrete insufficient amounts of GH, and that many of these very short children show an improvement in growth rate during treatment with physiological doses of GH.

Russell-Silver syndrome

Images

Activation of fatty acid oxidation in the Silver-Russell syndrome and the Brachmann-de Lange syndrome

We describe a similar metabolic pattern of hyperketosis, ketonaciduria, and C6-C12 dicarboxylic aciduria in a patient with the Silver-Russell syndrome and a patient with the Brachmann-de Lange syndrome. Fasting blood levels of beta-hydroxybutyrate and acetoacetate were significantly higher than in age-matched controls, and both patients showed massive urinary excretion of beta-hydroxybutyrate, acetoacetate and C6-C12 dicarboxylic acids.

Adolescent growth and pubertal progression in the Silver-Russell syndrome

The pattern of growth and development of 18 adolescent children with the Silver-Russell syndrome was studied. Mature height was about -3.6 standard deviation scores in both sexes. This is comparable to the height reduction at diagnosis, which has been reported previously. The pattern of puberty and adolescent growth was essentially normal and occurred at a marginally earlier time than normal, although in this small series the differences were not significant. In the girls there was a tendency to gain subcutaneous fat after puberty. This trend was not apparent in the boys.