98 Spondyloepimetaphyseal Dysplasia, Irapa Type
Spondyloepimetaphyseal Dysplasia, Irapa Type 881
SEMD Irapa type, SEMDIT
Disproportionately short stature, short spine, meta- carpals and metatarsals, severe osteoarthritis of hips and elbows
Frequency: Rare (fewer than 50 documented cases).
Genetics
Autosomal recessive (OMIM 271650).
Clinical Features
• Moderately short-trunk dwarfism stature (severe dwarfism in some cases)
• Pectus carinatum
• Lumbar lordosis
• Genu varum/valgum
• Rhizomelic limb shortening
• Short hands
• Short feet, pes planus
• Contractures, swollen joints, arthralgias
• Full extension of elbows limited
• Gait disturbances due to premature coxarthrosis Differential Diagnosis
• Other spondyloepimetaphyseal dysplasias
• Spondyloepiphyseal dysplasia congenita
• Pseudoachondroplasia
• Multiple epiphyseal dysplasia
Radiographic Features Spine
• Generalized platyspondyly (most pronounced at thoracic level)
• End-plate irregularity, Schmorl nodes (thoracic and lumbar spine)
• Scoliosis (not mandatory)
• Normal cervical spine
Generalized Skeletal Abnormalities
• Epiphyseal ossification delay
• Wide metaphyses and irregular epiphyses at the proximal femur and distal humerus
• Osteopenia
• Early-onset severe osteoarthritis (all joints, most pronounced in hips and elbows)
Limbs
• Rhizomelic shortening of long bones
• Normal humeral heads and shoulders
• Proximal radius subluxation Pelvis
• Short femoral necks, coxa vara
• Hypoplastic ilia and acetabular roofs
• Irregular symphysis pubis Hands and Feet
• Osteoarthritis of radiocarpal and metacarpopha- langeal joints
• Small irregular carpals, carpal fusion (capitate- hamate)
• Irregular shortening of metacarpals and meta- tarsals
• Distal widening of metacarpals
Bibliography
Arias SA. Etiologia multiple del enanismo entre los Indios Yukpa (Irapa) de le Sierra de Perija llamados “pigmoides”.
Bol Indigen Venezol 1976; 17: 49–70
Arias SA, Mota M, Pinto-Cisternas J. L’ostéochondrodysplasie spondylo-metaphysaire type Irapa: nouveau nanisme avec rachis et metatarsiens courts. Nouv Presse Med 1976; 5:
319–23
Cantù JM. Osteochondrodysplasia Irapa type: an ethnic mark- er gene in two subcontinents. Am J Med Genet 1981; 8:
251–6
Hernandez A, Ramirez ML, Nazara Z, Ocampo R, Ibarra B, Cantù JM. Autosomal recessive spondylo-epi-metaphyseal dysplasia (Irapa type) in a Mexican family: delineation of the syndrome. Am J Med Genet 1980; 5: 179–88
Kozlowski K, Budzinska A. Combined metaphyseal and epi- physeal dysostosis. Am J Radiol 1996; 97: 21–30
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Spondyloepimetaphyseal Dysplasia, Irapa Type 882
Fig. 98.1. a Patient 1, age 6 years. b Patient 2, age 32 years, father of patient 1. c Patient 3, age 35 years. Different degrees of short stature are seen in the three patients. Other noticeable features are rhizomelic limb shortening; limitation on full ex-
tension of elbows; lower limb deformities, including genu varus/valgus, pes planus; and positioning of feet, which are stretched apart to maintain the upright position. (Reprinted, with permission, from Arias et al. 1976)
a b c
Spondyloepimetaphyseal Dysplasia, Irapa Type 883
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Fig. 98.3. Patient 4, age 53 years. Severe osteoarthritis of hips, shortening of femoral necks, and coxa vara deformity.
(Reprinted, with permission, from Arias et al. 1976) Fig. 98.2. Patient 2, age 32 years. Note generalized platy-
spondyly, end-plate irregularities, marginal osteophytes, and Schmorl nodes. (Reprinted, with permission, from Arias et al.
1976)
Fig. 98.4. aPatient 2, age 32 years.
bPatient 5, age 25 years. Note ir- regular shortening of metacarpals and metatarsals, radiocarpal osteo- arthritis, and osteoarthritis of metacarpophalangeal joint, with severe changes of distal portions of metacarpals (widening, cyst formation). (Reprinted, with per- mission, from Arias et al. 1976)
a b
