317Case reports

Familial pericentric inversion (10) and its effect on two offspringMARIA TERESA RODRIGUEZ, MARIA JOSE MARTIN, ANDJOSE ANTONIO ABRISQUETAInstituto de Gen&tica, CSIC, Madrid, Spain.

SUMMARY A pericentric inversion (10)(p15q24)was observed in three generations of a family.One daughter of the inversion carrier was foundto have the inv(10) and trisomy 18. The otheroffspring had a recombinant (10) chromosome.Received for publication 3 January 1984.Accepted for publication 15 January 1984.

Case reportA pericentric inv(10)(pl5q24) was observed in threegenerations of a family. The family came to ourattention when the proband (111.5, fig 1) was born,showing clinical features of Edwards' syndrome.She was born at 40 weeks' gestation after a normalpregnancy. Birth weight was 1780 g. She died at 10

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naIrversion 10 and trisorry 18

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FIG 1 Family pedigree.

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FIG 2 GTG banded metaphase from the proband (III.S) showing the inverted and normal chrom?osomes 10 (long arrowts)and the trisomYv 18 (short arrows).

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3a('se report.s

days She was the second child of uiirelated parenits;the mother was 35 and the father 48 years old.Another malforimed child was born to the same

couple one year later. This second child (111.6)was a boy also born at term after- an LineventfLilpregnancy.The aniniotic fluid was mecolLiullm stained. Apgar

score was 9 at I minute. At birth he weighed 2000 g,length was 51 cm, and head circuliiiference 26 cim.Dysmorphic features included dolichocephaly, highanid large forehead, arched eyebrows, microph-thalmia, hypertelorisni (interpupillary distance 3 5cim ), epicanthus, antimongoloid slanits, narrowpalpebral fissures, flat and broad nose bridge, higharched palate, prominent upper lip, microretrog-nathia, low set ears, long thin fingers, ulniar handdeviation, clinodactylv, aiid a gap between the first

and seconid toes. Examination of the chest and heartwas norimial. At 21 nionths of age, he weighed 4180 gand his head circunliferenice was 39 5 cm.

(Y1 OGENETIC STUDIES

Chromilosome analyses of cultured lymphiocytes byQ, G, and T banding were performed. The proband'skaryotype was 47,XX,inv(l0)(pl5q24), 1l8 (fig 2).The inv('l0) was also present in her niother. Thefathier's chromosomes were normal. The sameinversion was found in four other niembers of thefamily (1:.2, 11.7, rl1.4, and 111.8).The second child (111.6) carried a recombinant

abinorimial chromosome 10: 46,XY,rec( 1 0)dup q,inv(10)(pl5q24)nmat (fig 3). Therefore the boy had aduplication of l0q24 --q(er and a deletion of distalp15.

Fi( 3 GTG (and( QFQ /hati(/iiig of(a) tiormlichromosome 10, (b) inv(IO)(p15q124), anid (c)r-econiibinamti (10). duip qjinv(10)tpl5q24).

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Case reports

Discussion

Segregation analysis of the inversion through threegenerations showed a carrier to non-carrier ratio of4:3.As a direct result of the meiotic behaviour of the

inversion, a recombinant chromosome 10, similarto that described by Dutrillaux et al,' was found in111.6, who showed the clinical features of the partialtrisomy IOq syndrome.2

In addition to the risk related to the segregationof the inverted chromosome itself, an interchromo-somal effect may also exist which could influencenon-disjunction involving another chromosomalpair.The existence of this chromosomal interference in

animals has been demonstrated, particularly inDrosophila.3 In man, this effect has been observedmainly in balanced translocations4 and in only a fewinstances of pericentric inversions (excluding thoseaffecting chromosome 9).5-9

In the present family, the occurrence of trisomy18 in the offspring of an inversion carrier adds tothe evidence supporting this type of chromosomaleffect. However, the age of the parents (35 and 48)may also have contributed to the aneuploidy.

Nevertheless with regard to genetic counselling,in addition to the risk directly attributed to thebalanced rearrangement, the influence of an inter-chromosomal effect should also be considered.

We thank Teresa Zorita, Antonio del Mazo,Amparo Cerrajero, and Victoria Lafita for technicalassistance, and the FNAS (Ministerio de Sanidad ySeguridad Social) for their support.

References

Dutrillaux B, Laurent C, Roberts JM, Lejeune J. Inver-sion pericentrique, inv(10), chez la mere et aneusomie derecombinaison, inv(10)rec(10), chez soni fils. Cy,togenetCell Genet 1973;12:245-53.

2 de Grouchy J, Turleau C. Atlas tles mtialadies clhro,no-somiques. 2nd ed. Paris: Expansion Scientifique Fran-gaise, 1982:178-95.Schultz J, Redfield H. Interchromosomal effect oncrossing-over in Drosophila. Coltd Spring Harbor Sp-In-posium on Quantitatii'e Biology 1951;16:175.Wolstenholme J, Faed MJW, Robertson J, Lamont MA.Chromosome abnormality in couples with histories ofmultiple abortions. The outcome of pregnancies sub-sequent to ascertainment and a study of familial trans-location carriers. Himni Genet 1983;63:45-7.

5 Wikramanayake E, Renwick JH, Ferguson-Smith MA.Chromosomal heteromorphisms in the assignment ofloci to particular autosomes: a study of four pedigrees.Ann Genet (Paris) 1971; 14:245-56.

6 Catti A. Inversions familiales et autres aberrationschromosomiques concomitantes. J Genet Hum 1975;suppl 23:92-5.

7 Hamerton JL, Canning N, Ray M, Smith S. A cyto-genetic survey of 14,069 newborn infants. I. Incidence ofchromosome anomalies. Clin Genet 1975;8:223-43.

8 Leonard C, Hazael-Massieux P, Boequet L, Larget-Piet L, Boue J. Inversion pericentrique inv(2)(pllql3)dans des familles non apparentees. H!Iunangenetik 1975;28:121-8.

9 Yunis E, Torres de Caballero 0. Duplication deficiencyas the result of meiotic segregation of a maternal inv(10).Hmni Genet 1981 ;57:71-4.

Correspondence and requests for reprints to DrM T Rodriguez, Instituto de Genetica, Valazquez144, Madrid 6, Spain.

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