Definition: Roberts syndrome is a rare developmental disorder, characterized by multiple malformations, in particular symmetrical limb reduction, craniofacial anomalies, such as bilateral cleft lip and palate, nose and ear anomalies, and severe mental and growth retardation. It was initially described by Roberts in 1919, and more recently reviewed by Appelt[1]^,[2]. Herrmann described in 1974, cases of a very similar entity called pseudothalidomide or SC syndrome[3]. I had wondered for a long time what the meaning of the SC was. It is simply the initial of the two families that were originally described. Nowadays Roberts syndrome and SC phocomelia are considered a single genetic entity, with a wide phenotypic variation[4].

Incidence: Unknown.

Etiology: This disorder has an autossomal recessive transmission with marked variability of phenotypic expression. The unique cytogenetic abnormality, called premature centromere separation, which disrupts the process of chromatid pairing, is responsible for the development of multiple structural anomalies found in Roberts syndrome[5].

Recurrence Risk: The recurrence risk for couples with positive family history is 25%.

Diagnosis: The presence of midfacial clefts (lip and palate), nose and ears abnormalities, facial hemangioma, hypertelorism, microcephaly, curly silvery blond hair, tetraphocomelia, severe growth and mental retardation is very suggestive of Roberts syndrome[6]^,[7],[8]. Less common findings include oligodactyly, cryptorchidism, enlarged phallus (compared to rest of the body), oligohydramnios, renal anomalies (polycystic or dysplastic kidneys), heart defects (in particular atrial septal defect and patent ductus arteriosus), gastrointestinal abnormalities (obstructions). Sonographic detection of those features is highly indicative of Roberts syndrome. Clinical findings and cytogenetic studies make the diagnosis after birth.

Genetic anomaly: Cytogenic analysis of fetal cells, obtained from chorionic villi sample at the first trimester, amniocentesis or cordocentesis during the second and third trimesters, is required to confirm the diagnosis prenatally. The presence of premature centromere separation makes the diagnosis. One negative cytogenetic analysis does not exclude Roberts syndrome. A second analysis using a different type of fetal tissue is required.

Prognosis: Most patients born at term with less than 37cm of birth length and severe facial and limb defects have been stillborn or have died early in childhood. Patients born with more than 37cm of birth length and less severe defects have better prognosis4. However, survival beyond the infancy is infrequent.

Management: When detected before viability, termination of pregnancy can be offered. After viability, standard obstetrical management is not altered. For those families previously affected, chorionic villi sample for cytogenetic studies during the first trimester must be offered.

References:

[1] Roberts JB. Achild with double cleft of lip and palate, protrusion of the intermaxillary portion of the upper jaw and imperfect development of the bones of the four extremities. Ann. Surg., 1919, 70: 252

[2] Appelt H, Gerken H, Lenz W. Tetraphokomelie mit Lippen-Kiefer-Gaumenspalte und Clitorishypertrophie - Ein Syndrom. Paediatr. Paedol., 1966, 2: 119

[3] Herrmann J, et al. A familial dysmorphogenetic syndrome of limb deformities, characteristic facial appearance and associated anomalies: The pseudothalidomide or SC-syndrome. Birth Defects, 1969, 5: 81

[4] Jones KL. Roberts-SC Phocomelia in Smith"s recognizable patterns of human malformation, W.B. Saunders Company - Philadelphia, Pennsylvania. 1997, 298-299

[5] German J. Roberts syndrome 1. Cytological evidence for a disturbance in chromatid pairing. Clin. Genet., 1979, 16: 441-447.

[6] Robins DB, Ladda RL, Thieme GA, Boal DK, Emanuel BS, Zackai EH. Prenatal detection of Roberts-SC Phocomelia syndrome: Report of 2 sibs with characteristic manifestations. Am. J. Med. Genet., 1989, 32: 390-394

[7] Stioui S, Privitera O, Brambati B, Zuliani G, Lalatta F, Simoni G. First-trimester prenatal diagnosis of Roberts syndrome. Prenat. Diagn., 1992, 12: 145-149

[8] Palladini D, Palmieri S, Lecora M, Perone L, Di Meglio A, D"Armiento M, Cascioli C, Martinelli P. Prenatal ultrasound diagnosis of Roberts syndrome in a family with  negative history. Ultrasound Obstet. Gynecol., 1996, 7: 208-210