Amelia Villa

Proximal partial 5p trisomy resulting from a maternal (19;5) insertion

We present a case with a partial duplication 5p11-->5p13.3 resulting from a maternal ins (19,5)(p11;p11-p13.3). The diagnosis was confirmed by FISH and complement component determinations. The clinical picture was similar to those described in patients with complete duplication of the short arm and in some patients with partial 5p duplications, affecting at least band 5p13. A special significance of band 5p13 in the clinical severity of 5p duplications is discussed.

Interstitial tandem duplication of 6p: A case with partial trisomy (6)(p12p21.3)

A de novo interstitial tandem duplication of 6p12p21.3 was observed in a 7-month-old boy with growth retardation, psychomotor delay and craniofacial, brain, limb, and genital anomalies. Fluorescent in situ hybridization using a chromosome 6 paint probe demonstrated that the extra material belonged to chromosome 6. Although it has been suggested that 6p25 is the critical band involved in the expression of the phenotype of 6p duplication, comparison of the clinical findings of this case with those from the literature cases showed strong similarities.

Ring chromosome 7 and sacral agenesis

A ring chromosome 7 was found in a 19-month-old girl with microcephaly, growth and developmental delay, multiple angiomas, and partial sacral agenesis. Absent sacrum is a frequent finding in patients with 7q terminal deletions; in fact, genes involved in the sacral agenesis are localized in 7q36. However, this anomaly was not described previously in patients with a ring chromosome 7. High resolution G-banding chromosome and fluorescence in situ hybridization (FISH) demonstrated that our patient lost this region during ring formation.

Tetrasomy 5p mosaicism due to an extra i(5p) in a severely affected girl

We present a case of mosaic 5p tetrasomy. The mosaicism 46,XX/47,XX,+i(5p) was found at different ratios in blood lymphocytes, skin fibroblasts, and chondrocytes. The origin of the extra isochromosome was confirmed by FISH. The clinical picture corresponds to that described in trisomy 5p patients, although it was more severe than the two previously reported cases of mosaic 5p tetrasomy. No correlation between clinical severity and proportion of tetrasomic cells in blood or fibroblasts was found in these cases.

Giant-cell chondrodysplasia in a male infant with clinical and radiological findings resembling the Piepkorn type of lethal osteochondrodysplasia.

We report on a patient whose clinical, radiologic, and histopathologic findings are compatible with the Piepkorn type of lethal short-limb osteochondrodysplasia, but who also showed multinucleated giant chondrocytes in cartilage. Multinucleated giant cells are an unusual finding in osteochondrodysplasias, having been reported in atelosteogenesis type I and boomerang dysplasia. This uncommon histopathologic finding and the clinical and radiographic findings strongly support the diagnosis of boomerang dysplasia in the present patient. Our patient supports the previously suggested existence of an entity including atelosteogenesis and boomerang dysplasia. If this is so, the current patient and that described by Piepkorn et al. [1977: Teratology 16:345-350] could represent the most severe clinical expression of that condition.

Limb deficiencies in infants with trisomy 13

In 1994, we published a case with trisomy 13 who presented with ectrodactyly [Urioste et al., 1994: Am J Med Genet 53:390-392]. Recently, Kuschel and Gillessen-Kaesbach [2000: Am J Med Genet 90:87-88] presented an infant with trisomy 13 who also had oligodactyly, and they considered their case as the second published with oligodactyly. Here, we present three cases with any type of limb deficiencies who, together with the one that was published previously [Urioste et al., 1994], correspond to the total of 75 cases with trisomy 13 identified in the Spanish Collaborative Study of Congenital Malformations (ECEMC). This gives us a minimum frequency of 5.33% (CI:1.45-13.65) for trisomy 13 cases having limb deficiencies whereas these defects have a frequency of 5.51 per 10,000 births in our population. Consequently, we think that limb deficiencies could be considered as one of the defects that constitute the spectrum of anomalies observed in infants with trisomy 13.