93 Short Rib-Polydactyly Syndrome, Type I
SRP syndrome 1, Saldino-Noonan and Verma-Naumoff types included
Lethal dwarfism, severe micromelia, narrow thorax, postaxial polysyndactyly, hydrops
Frequency: Rare (fewer than 100 published cases).
Genetics
Autosomal recessive (OMIM 263530); type III short rib-polydactyly syndrome (Verma-Naumoff, OMIM 263510), originally described as a separate entity, may be the same as Saldino-Noonan syndrome with milder changes in long bones and pelvis.
Clinical Features
• Lethal dwarfism, identifiable at birth
• Hydrops fetalis, oligohydramnios, preterm deliv- ery
• Severe micromelia, ‘flipper’-like limbs, postaxial polysyndactyly, nail dysplasia
• Flat face and occiput (Potter-like face)
• Cleft lip and/or palate, cleft tongue, furrowed alve- olar ridges
• Low-set, flattened, deformed ears
• Narrow constricted thorax, pulmonary hypoplasia
• Protruding abdomen
• Cardiovascular defects (transposition of great ar- teries, ventricular septal defect, double-outlet left ventricle, persistence of left superior vena cava)
• Gastrointestinal and genitourinary atresia, poly- cystic kidneys, pancreatic fibrosis and cysts, ab- normal cloacal development, hypoplastic penis, cryptorchidism (in males with 46,XY karyotype complete sex reversal may occur)
Differential Diagnosis
• Short rib-polydactyly syndrome type II (Majewski):
more normal appearance of pelvis, smooth meta- physeal margins of long bones, disproportionate shortening of tibias.
• Short rib-polydactyly syndrome type IV (Beemer- Langer): smooth metaphyseal margins of long bones, tibias longer than fibulas, bowing of radius and ulna.
• Asphyxiating thoracic dysplasia
• Chondroectodermal dysplasia
Radiographic Features Generalized Bone Defects
• Deficient ossification of calvaria, vertebrae, pelvis, bones of hands and feet
Chest
• Narrow thorax, with severely short, horizontally oriented ribs
• Small scapulae
• Superiorly located, deformed clavicles Extremities
• Extremely short tubular bones with pointed or ragged ends
• Metaphyseal spurs
• Notched tibias
• Absent fibulas (not mandatory)
• Poorly ossified metacarpals, metatarsals, and pha- langes
• Postaxial hexa- or heptadactyly, often with cuta- neous syndactyly
Pelvis
• Small iliac bones
• Flattened acetabular roofs
• Medial and lateral osseous acetabular spurs
• Short sacroiliac notches
Short Rib-Polydactyly Syndrome, Type I 866
Fig. 93.1. Patient 1, stillborn. Note hydropic appearance; mi- cromelia; frontal bossing; flat, Potter-like face; small thorax;
and protruding abdomen. (Reprinted, with permission, from Mastroiacovo et al. 1990)
Skull
• Dolichocephaly
• Poor mineralization of frontal bones
• Hypoplasia of mandible Spine
• Distorted, flattened or squared, irregular vertebral bodies
• Hypoplastic cervical vertebrae
• Coronal cleft of vertebral bodies
Bibliography
Bernstein R, Isdale J, Pinto M, Zaaijman JT, Jenkins T. Short rib-polydactyly syndrome: a single or heterogeneous enti- ty? A re-evaluation prompted by four new cases. J Med Genet 1985; 22: 46–53
Canepa G, Maroteaux P, Pietrogrande V. Sindromi dismorfiche e malattie costituzionali dello scheletro. Piccin, Padova, 1996
Lowry RB, Wignall N. Saldino-Noonan short rib-polydactyly dwarfism syndrome. Pediatrics 1975; 56: 121–2
Martinez-Frias ML, Bermejo E, Urioste M, Huertas H,Arroyo I.
Lethal short rib-polydactyly syndromes: further evidence for their overlapping in a continuous spectrum. J Med Genet 1993; 30: 937–41
Mastroiacovo P, Dallapiccola B,Andria G, Camera G, Lungarot- ti MS. Difetti congeniti e sindromi malformative. McGraw- Hill, Milan, 1990
Sarafoglou K, Funai EF, Fefferman N, Zajac L, Geneiser N, Paidas MJ, Greco A, Wallerstein R. Short rib-polydactyly syndrome: more evidence of a continuous spectrum. Clin Genet 1999; 56: 145–8
Sillence D, Kozlowski K, Bar-ziv J, Fuhrumann-Rieger A, Fuhrmann W, Pascu F. Perinatally lethal short rib-poly- dactyly syndromes. 1. Variability in known syndromes.
Pediatr Radiol 1987; 17: 474–80
Spranger JW, Grimm B, Weller M, Weibenbacher G, Herrmann J, Gilbert EF, Krepler R. Short rib-polydactyly (SRP) syn- dromes, types Majewski and Saldino-Noonan. Z Kinder- heilkd 1974; 116: 73–94
Short Rib-Polydactyly Syndrome, Type I 867
S
Fig. 93.2. Patient 2, stillborn. Thorax is narrow, with severely shortened, horizontally oriented ribs. Abdomen is protruding.
Severe limb shortening, with irregular metaphyses (ragged, with medial and lateral spurs). Scapulae are markedly small.
Clavicles are superiorly located, thin, and elongated. Iliac bones are short, with narrow sciatic notches and flat, trident- like acetabula. Both feet and hands are poorly ossified. This phenotype, with relatively well formed tubular bones, fits better the original description of the Verma-Naumoff type of short rib-polydactyly syndrome. (Reprinted, with permission, from Canepa et al. 1996)
