Partial trisomie 5q: Three different phenotypes depending on different duplication segments

Summary

On the basis of phenotypic similarities and differences among patients with a partial trisomy of chromosome 5q, three clinically distinguishable phenotypes are suggested. Each corresponds to a distinct abnormal karyotype in which there is partial duplication of a different segment of the long arm of chromosome 5 (5q+). The hypothesis is derived from 12 published cases of partial trisomy 5q, and from 2 additional new cases of partial trisomy 5q31→qter in a family with a balanced translocation, t(5;11)(q31;q25), in the father. The partial duplications and their corresponding phenotypes are as follows:

• A. A proximal duplication, 5q11→5q22, associated with musculoskeletal abnormalities including general hypotrophy, severe muscular asthenia, severe psychomotor retardation, lordosis, scoliosis, spina bifida occulta, protruding sternum, cubitus valgus and genu valgum, dysmorphic face with short nose and thick upper lip, bulging forehead, thin tapering fingers, no simian creases, and dermatoglyphic peculiarities;

• B. A distal duplication, 5q31(32/33)→qter, associated with severe retardation of growth and of psychomotor development, microcephaly, epicanthus, strabismus, hypertelorism, antimongoloid slants of the eyes, large upper lip, carpmouth, dental caries, lowset, dysplastic, protruding ears, brachydactyly and clinodactyly, hernias, cardiac malformations, dermatoglyphic abnormalities, and reduced life expectancy;

• C. A distal duplication, 5q34→ter, associated with short stature, mild mental retardation, delayed puberty, chronic eczema, hernias, dysmorphic facies including short receding forehead, high nasal bridge, thick alae nasales, prominent nasal tip, dental caries, digital anomalies and normal life expectancy.