Donetsk`s regional specialized center of medical genetic and prenatal diagnosis, Ukraine.
Synonyms: Russell-Silver syndrome, Silver-Russell dwarfism, Russell nanism, Russell syndrome.
Silver-Russell syndrome is a clinically heterogeneous condition characterized by severe intrauterine growth retardation with normal head circumference, poor postnatal growth, craniofacial features such as a triangular shaped face and a broad forehead, body asymmetry, and a variety of minor malformations. The phenotypic expression changes during childhood and adolescence. There can be a limb-length asymmetry resulting from the hemihypotrophy with decreased growth of the affected side. The facial features and asymmetry usually becomes more subtle with the age.
Variation in sexual development in association with hypospadias and cryptorchidism is present in about one third of the affected individuals. Urinary tract abnormalities include hydronephrosis, ureteral obstruction, pyelonephritis, urinary reflux, and kidney enlargement. Affected individuals may have feeding difficulties and fasting hypoglycemia.
Uncommon, varies from 0.1-3 in 10,000 births, the male-to-female ratio is equal.
This syndrome is a heterogenous condition. Most affected individuals represent the same phenotype rather than a specific disorder. The final diagnosis is mainly based on the clinical findings. 10% of affected individuals have maternal uniparental disomy for chromosome 7 (7q25). Some individuals have epigenetic mutations of the imprinted region of chromosome 11p15.5. Hypomethylation of this region represents a major cause of the disorder. Opposite epigenetic mutations, hypermethylation at the same region, are observed in about 5 to 10 % of patients with Beckwith-Wiedemann syndrome.
Usually, no alteration of the prenatal care is necessary.
A 21-year-old G2 P0 Caucasian woman, was referred to our unit for prenatal examination. Her previous pregnancy was terminated at 20 weeks of gestation due to hydrocephalus. The patient was of a very short stature, 146 cm, she had a clinodactyly of the 5th finger, a skin with Café-au-lait spots, a small triangular face, prominent forehead, mandibular micrognathia with a pointed chin, wide mouth with down-turned corners. The mother of our patient had a very similar phenotype.
Our ultrasound examination at 18 weeks revealed fetus with an incipient symmetrical growth restriction, biometry corresponded to 17 weeks of gestation. There was a mild dilation of the lateral ventricles, 9 mm and ambiguous genitalia. No other fetal anomalies were detected. A triple screen was negative.
Our follow-up examination two weeks later revealed a further growth restriction, ventriculomegaly, hypospadia and facial dysmorphism and clinodactyly of the 5th finger.
Our diagnosis based on the ultrasound findings was Silver-Russell syndrome. Patient decided to continue her pregnancy. Amniocentesis showed normal karyotype, 46 XY. Patient delivered at term, the newborns's weight was 2200 grams. A geneticist confirmed our prenatal diagnosis of Silver-Russell syndrome.
Images 1,2: Image 1 shows a fetal profile. Image 2 shows a lateral ventricle measuring 9 mm.
Images 3,4: 3D-images of the fetal face. Note small triangular facies, high forehead and small jaw, micrognathia with pointed chin and down-turned corners of the mouth.
Images 5,6: Image 5 shows a 3D-image of normal spinal column. Image 6 shows clinodactyly, hypoplasia of the middle phalange of the 5th finger.
Images 7,8: Image 7 shows a fetal genitalia. Image 8 shows a urinal jet directed downwards, typical for hypospadia.
Images 9,10: 3D-images of the genitalia which resemble ambiguous genitalia.
Images 11-14: Images of the neonate. Note the the dysmorphic facial features, triangular face, high forehead that tapers to a small jaw, micrognathia with a pointed chin, prominent nasal bridge, and down-turned corners of the mouth.
Image 15,16: Image of the fetal genitalia, note penile hypospadia and right-sided cryptorchidism.
1. OMIM: http://www.ncbi.nlm.nih.gov/omim/180860
2. Bartholdi, D., Krajewska-Walasek, M., Ounap, K., Gaspar, H., Chrzanowska, K. H., Ilyana, H., Kayserili, H., Lurie, I. W., Schinzel, A., Baumer, A. Epigenetic mutations of the imprinted IGF2-H19 domain in Silver-Russell syndrome (SRS): results from a large cohort of patients with SRS and SRS-like phenotypes. J. Med. Genet. 46: 192-197, 2009.
3. Orphanet journal of rare diseases: http://www.ojrd.com/content/5/1/19
4. Emedicine: http://emedicine.medscape.com/article/948786-overview