Humangenetik 28, 1--8 (1975) © by Springer-Verlag 1975
Original Investigations A 46,XX,10q+ Chromosome Constitution in a Girl. Partial Long Arm Duplication or Insertional Translocation? E. Orye, H. V e r h a a r e n , K . S a m u e l , a n d B. v a n Mele Laboratory of Cytogeneties, Department of Pediatrics, gijksuniversiteit Gent, Belgium l%eceived January 23, 1975
Summary. A girl with slight psychomotor retardation, microphthalmia, and colobomata of the left eye, a hypotrophy of the right arm and a surnmnerary digit on the right hand is described. The routine chromosome analysis and a G-banding analysis revealed an elongated long arm of chromosome 10. An extra light and dark band was present proximally. Both parents had normal chromosomes. While the visual comparison of the abnormal with the normal chromosome 10, did not enable the extra bands of the normal bands q21 and q22 to be distinguished. However, measurements of length, surface area, and relative reflection of the different light and dark bands of the long arm on tracings or directly on the normal and abnormal chromosomes, enabled us to precisely locate the extra bands and to determine that the abnormal chromosome was a result of an insertional translocation. The value of such measurements is discussed. With the new chromosome banding techniques the type of and the chromos o m e s i n v o l v e d in c o m p l e x c h r o m o s o m e r e a r r a n g e m e n t s c a n n o w be i d e n t i f i e d a c c u r a t e l y (Grace et al., 1972; F r a n c k e , 1972; T h e r k e l s e n et al., 1973; H i r s c h h o r n et al., 1973; Y a n a g i s a w a , 1973). H o w e v e r , e v e n w i t h t h e s e t e c h n i q u e s it is n o t a l w a y s e a s y t o r e c o g n i z e t h e t y p e of s t r u c t u r a l a b e r r a t i o n p r e s e n t . I n t h e girl d e s c r i b e d here, o n l y a c c u r a t e m e a s u r e m e n t s o n t h e b a n d e d a b n o r m M c h r o m o s o m e 1 0 q @ e n a b l e d its o r i g i n to be defined.
Case Report The proband, born on 21 September 1970, was the third child of a 37-year-old mother and a 36-year-old father. Both parents and the two older children, a 7-year-old girl and a 5-year-old boy, are healthy. There is no consanguinity and the family history is negative. Except for a hyperemesis gravidarum in the first month, the pregnancy was uneventful. The mother had not been exposed to X-ray, took no medication, and did not smoke during pregnancy, tIistory revealed no infections. The child was born at term after a normal delivery. Her birth weight was 2650 g. On the 6 November 1972 the patient was seen for the first time in our department and year later again on 7 December 1973. On physical examination at the age of 3 years and 2 months the girl was thin and dystrophic (Fig. 1). Her length was 91.5 cm (P10--P15), her weight 10 kg (
Original Investigations A 46,XX,10q+ Chromosome Constitution in a Girl. Partial Long Arm Duplication or Insertional Translocation? E. Orye, H. V e r h a a r e n , K . S a m u e l , a n d B. v a n Mele Laboratory of Cytogeneties, Department of Pediatrics, gijksuniversiteit Gent, Belgium l%eceived January 23, 1975
Summary. A girl with slight psychomotor retardation, microphthalmia, and colobomata of the left eye, a hypotrophy of the right arm and a surnmnerary digit on the right hand is described. The routine chromosome analysis and a G-banding analysis revealed an elongated long arm of chromosome 10. An extra light and dark band was present proximally. Both parents had normal chromosomes. While the visual comparison of the abnormal with the normal chromosome 10, did not enable the extra bands of the normal bands q21 and q22 to be distinguished. However, measurements of length, surface area, and relative reflection of the different light and dark bands of the long arm on tracings or directly on the normal and abnormal chromosomes, enabled us to precisely locate the extra bands and to determine that the abnormal chromosome was a result of an insertional translocation. The value of such measurements is discussed. With the new chromosome banding techniques the type of and the chromos o m e s i n v o l v e d in c o m p l e x c h r o m o s o m e r e a r r a n g e m e n t s c a n n o w be i d e n t i f i e d a c c u r a t e l y (Grace et al., 1972; F r a n c k e , 1972; T h e r k e l s e n et al., 1973; H i r s c h h o r n et al., 1973; Y a n a g i s a w a , 1973). H o w e v e r , e v e n w i t h t h e s e t e c h n i q u e s it is n o t a l w a y s e a s y t o r e c o g n i z e t h e t y p e of s t r u c t u r a l a b e r r a t i o n p r e s e n t . I n t h e girl d e s c r i b e d here, o n l y a c c u r a t e m e a s u r e m e n t s o n t h e b a n d e d a b n o r m M c h r o m o s o m e 1 0 q @ e n a b l e d its o r i g i n to be defined.
Case Report The proband, born on 21 September 1970, was the third child of a 37-year-old mother and a 36-year-old father. Both parents and the two older children, a 7-year-old girl and a 5-year-old boy, are healthy. There is no consanguinity and the family history is negative. Except for a hyperemesis gravidarum in the first month, the pregnancy was uneventful. The mother had not been exposed to X-ray, took no medication, and did not smoke during pregnancy, tIistory revealed no infections. The child was born at term after a normal delivery. Her birth weight was 2650 g. On the 6 November 1972 the patient was seen for the first time in our department and year later again on 7 December 1973. On physical examination at the age of 3 years and 2 months the girl was thin and dystrophic (Fig. 1). Her length was 91.5 cm (P10--P15), her weight 10 kg (
