87 Roberts Syndrome
Roberts Syndrome 849
RBS, Roberts-SC phocomelia syndrome, pseudothalidomide syndrome
Tetraphocomelia, cleft lip/palate, ectrodactyly/malpo- sition of thumbs, hypertelorism, exophthalmos Frequency: Rare (over 100 cases reported).
Genetics
Autosomal recessive (OMIM 268300); the disease locus maps to chromosome 8p21; premature cen- tromere separation; chromosome puffing of hetero- chromatic regions around the centromeres and nucleolar organizers.
Clinical Features
• Severe growth retardation (pre-/postnatal)
• Microcephaly (80%), sparse hair
• Hypertelorism, prominent eyes, eyelids coloboma, corneal opacity, cataracts
• Wide nasal bridge, hypoplastic nose, facial hem- angioma
• Midfacial cleft (80%), usually bilateral cleft lip/
palate, prominent premaxilla, delayed eruption of permanent teeth
• Dysplastic ears, hypoplastic lobes
• Tetramelic, asymmetrical limb reduction, hypo- plastic/absent limb bones, oligodactyly, syndacty- ly
• Renal dysplasia, polycystic kidneys, heart defects, variable brain malformations, hypogonadism
• Thrombocytopenia
• Flexion contractions of several joints, including knees, ankles, wrists, and elbows (50%)
Differential Diagnosis
• Thalidomide embryopathy
• Baller-Gerold syndrome
• Trisomy 18
• Lethal Nager acrofacial dysostosis
• TAR syndrome
• DK-phocomelia syndrome
• Tetra-amelia with multiple malformations
Radiographic Features Limbs
• Asymmetrical reduction anomalies of variable degree in the long bones of all extremities (90%), ranging from mild hypoplasia to complete aplasia of arms and legs with rudimentary digits; upper extremities usually more involved than lower extremities, with humerus shorter than femur;
radius usually shorter than ulna
• Humeroradial/humeroulnar synostosis, femorotibial synostosis (10%)
• Radial deviation of hands
• Oligodactyly, asymmetrical shortening of fingers (80%), absent or hypoplastic phalanges (especial- ly 1st and 5th finger)
• Clinodactyly of index finger, soft tissue syndacty- ly (40%)
• Irregular carpal bones, decrease in number of carpal bones
• Clubfoot Skull
• Microbrachycephaly, oxycephaly, wormian bones, copper-beaten appearance
• Maxillary agenesis, cleft palate, frontal defect (encephalocele)
• Orbital hypertelorism
• Micrognathia Chest
• Fused, thin ribs, abnormal rib number Spine
• Spina bifida
• Platyspondyly, reduced intervertebral spaces
R
Bibliography
Allingham-Hawkins DJ, Tomkins DJ. Heterogeneity in Roberts syndrome. Am J Med Genet 1995; 55: 188–94
Freeman MVR, Williams DW, Schimke RN, Temtamy SA. The Roberts syndrome. Clin Genet 1974; 5: 1–16
Mastroiacovo P, Dallapiccola B,Andria G, Camera G, Lungarot- ti MS. Difetti congeniti e sindromi malformative. McGraw- Hill, Milan, 1990
McDaniel LD, Tomkins DJ, Stanbridge EJ, Somerville MJ, Friedberg EC, Schultz RA. Mapping of a single locus capa- ble of complementing the defective heterochromatin phe- notype of Roberts syndrome cells. Am J Hum Genet 2005;
77: 132–9
Pavlopoulos PM, Konstantinidou AE, Agapitos E, Davaris P.
Cell proliferation rate and nuclear morphometry in Roberts syndrome. Clin Genet 1998; 54: 512–6
Sinha AK, Verma RS, Mani VJ. Clinical heterogeneity of skele- tal dysplasia in Roberts syndrome: a review. Hum Hered 1994; 44: 121–6
Urban M, Rogalla P, Tinschert S, Krietsch P. Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome. Am J Med Genet 1998; 79:
155–60
Van den Berg DJ, Francke U. Roberts syndrome: a review of 100 cases and a new rating system for severity. Am J Med Genet 1993; 47: 1104–23
Roberts Syndrome 850
Fig. 87.1.
Patient 1, newborn. Marked growth retardation, mid-facial cleft, pro- minent ocular globes, dysplastic ears, and severe tetramelic limb reduction. (Reprinted, with per- mission, from Mastroiacovo et al.
1990)
