A disorder associated with osseous syndactyly, mesomelic brachymelia, and frequent renal anomalies.
Cenani-Lenz Syndactyly; Cenani-Lenz Oligodactyly-Synostosis Syndrome.
Named after A. Cenani from Turkey and W. Lenz from Germany, two medical geneticists who described this disorder in 1967, although earlier reports of this syndrome date back to as early as 1938.
Unknown, but approximately 40 patients have been described.
Most often autosomal recessive; however, quasidominant inheritance has also been described. In most cases, parental consanguinity is present. There is a fairly wide variability in the phenotype of this disorder. In the vast majority of cases, the underlying genetic defect is the result of (mainly) missense mutations with loss of function of the LRP4 (low density lipoprotein receptor-related protein 4) gene, which has been mapped to chromosome 11p11.2-q13.1. The protein encoded by the LRP4 gene seems to be involved in the regulation of embryonic limb patterning and kidney development, but also in the biosynthesis and function of the neuromuscular junction and acting as a co-receptor for agrin, a large proteoglycan that plays a role in the pre- and postsynaptic differentiation of the neuromuscular junction and the aggregation of acetylcholine receptors. Mutations in genes encoding other members of the agrin complex have been associated with akinetic and myasthenic syndromes in humans.
Based on the clinical findings and family history. Genetic molecular testing with confirmation of the LRP4 mutation may be helpful.
The main findings consist of short stature, distal limb malformations characterized by partial or total syndactyly/synostosis and/or oligodactyly of fingers and toes, and disorganization and fusion (syndactyly/synostosis) of metacarpals and metatarsals. The hand may resemble the “spoon hand” deformity of ☞Apert Syndrome. The ulna and radius may be fused (radioulnar synostosis) with mesomelic shortness of the upper limbs. The lower limb anomalies are principally similar, but usually less severe. Severe shortening of the tibiae and absent fibulae has only been described in one case. Congenital bilateral hip dislocations have been described and general joint mobility may be restricted. The nails may be absent or hypoplastic. Thoracic scoliosis with hemivertebrae, rib anomalies, and ☞diastematomyelia were present in one case. Uni- or bilateral renal agenesis or hypoplasia has now been detected in more than half of affected families, and genital anomalies, cavernous hemangiomas, and supernumerary nipples have been observed occasionally. Facial features may include a high, wide, prominent forehead, large dysplastic ears, malar hypoplasia, downslanting palpebral fissures, hypertelorism, short nose with depressed nasal bridge, short but prominent philtrum, high-arched palate, micro-/retrognathia, hypodontia, enamel dysplasia, early loss of teeth, and laryngomalacia. Developmental delay has been reported in a few patients.
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