842
Letters to the Editor
REFERENCES 1. Committee on Nutrition: Fluoride as a nutrient, Pediatrics 49:456, 1972. 2. Holliday MA: Letter to the Editor, Pediatrics 55:572, 1975. 3. Hodge HC: Fluorides in pediatrics, Am J Dis Child 128:291, 1974. 4. Margolis FJ, Reames HR, Freshman E, McCauley JC, and Mehaffey H: Fluoride: Ten year prospective study of deciduous and permanent dentition, Am J Dis Child 129:794, 1975.
More on twinning and cleft lip (palate) To the Editor." Doctors Armendares and Lisker 1have suggested that propositi with cleft lip + / - palate(CL[P]) are more likely to have been members o f a twin pair (2.3%) than are their sibs (0.47%). The sample from which this conclusion was drawn consisted of 215 families ascertained through an affected propositi. There were 1,058 pregnancies in these families, of which nine were twin pregnancies-five including an individual with CL(P). I should like to question the authors' claim for an increased frequency of twinning in pregnancies resulting in CL(P). From nine twin pregnancies there are 18 twins. If the distribution of twins is random, then one would expect (18/1,058 • 215) or about 3.6 propositi to be members of a twin pair. Five were found and the difference is not significant. Similarly (18-5)/ (1,058-215) • 100 or 1.5% of "nonpropositi" are members of a twin pair, and not 0.47% as stated by the authors. Finally the difference in twin frequency between propositi (5/215) and nonpropositi (13/843) is not significant. Alasdair G. W. Hunter, M.D. Department of Genetics The Hospital for Sick Children 555 University Ave. Toronto, Ont., Canada REFERENCE
1. Armendares S, and Lisker R: Twinning and cleft lip with or without cleft palate, J PEDIATR 86:479, 1975.
Reply To the Editor: We have read with interest the points raised by Dr. Hunter regarding our letter that appeared in the March issue o f THE JOURNAL OF PEDIATRICS. We do not agree with him but recognize that there might be an element o f confusion in our letter, and would like to make clear that we speak all the time of twinning and not of twins. In this context the findings were: In the 215 families ascertained, there were 1,058 pregnancies, nine of which resulted in twins. In five of these nine pregnancies, one of the twins had CL(P), giving a figure of 2.3% (5/215), against four
The Journal of Pediatrics November 1975
twin pregnancies in the other 843 pregnancies, or 0.47% (4/843). Probably the confusion arises from the phrase " . . . 5-fold more than that present in their nontwin sibs." These should perhaps read " . . . 5-fold more than that present in all pregnancies in which no affected child was present." Salvador Armendares, M.D. Rubbn Lisker, M.D. Seceibn de Genktiea Departamento de lnvestigacibn Cient(fica Apartado Postal 73-032 Mbxico 73, D.F
Partial trisomy 15 (dup l 5q) syndrome and the need for precision in clinical cytogenetics To the Editor: The article by Bannister and Engel 1 in the June issue is a good one. The title on the front cover--A G-like trisomy--is less good. The full title on the inside is not much better. One key reference ~ pertaining to Bannister and Engel's central topic also might be added to their brief list. The following sequential points may be made about the paper by Bannister and Engel: (1) Their patient did not have a G chromosome problem; (2) the maternal "interchange" was a translocation; (3) this translocation involved not merely a D and an E chromosome, but specifically Nos. 15 and 17; (4) the breakpoints in these chromosomes were not given, but appear to be at 15q22 and 17p13 (using the Paris international chromosome nomenclature J whereby q = long arm and p = short arm); (5) the mother's karotype should therefore be designated (using Paris nomenclature;9: 46,XX,t (15;17) (q22;p13); (6) the child had chromosome imbalance due to maternal nondisjunction; specifically; (7) the child had duplication (dup) of most o f the long arm of No. 15 and possibly of a small portion of the short arm of No. 17, ie, the child had dupl5q and ?dupl7p; and (8) the child's karyotype should, therefore, using Paris nomenclature ~ be designated: 47,XY, + t (15pter---~15q22::17p13-~17pter) where "ter" = "terminus of a chromosome," the arrow means "running from.., to," and the double colon means "broken and joined to." All of this is far from trivial. The title and the key words in a title are what are used for indexing a paper (particularly one without a summary or abstract) so that it can be accurately filed and retrieved from the literature. Since human cytogenetics has become more precise, so must the writing, editing, and entitling of papers. This precision must extend to the precise use of current nomenclature. The report by Bannister and Engel 1 is o f particular clinical value, because their patient very closely resembled another patient 4 reported three years ago. This suggests the existence of a distinct mental retardation/malformation syndrome due to dup 15q. Bannister and Engel are to be congratulated, if not upon
Letters to the Editor
REFERENCES 1. Committee on Nutrition: Fluoride as a nutrient, Pediatrics 49:456, 1972. 2. Holliday MA: Letter to the Editor, Pediatrics 55:572, 1975. 3. Hodge HC: Fluorides in pediatrics, Am J Dis Child 128:291, 1974. 4. Margolis FJ, Reames HR, Freshman E, McCauley JC, and Mehaffey H: Fluoride: Ten year prospective study of deciduous and permanent dentition, Am J Dis Child 129:794, 1975.
More on twinning and cleft lip (palate) To the Editor." Doctors Armendares and Lisker 1have suggested that propositi with cleft lip + / - palate(CL[P]) are more likely to have been members o f a twin pair (2.3%) than are their sibs (0.47%). The sample from which this conclusion was drawn consisted of 215 families ascertained through an affected propositi. There were 1,058 pregnancies in these families, of which nine were twin pregnancies-five including an individual with CL(P). I should like to question the authors' claim for an increased frequency of twinning in pregnancies resulting in CL(P). From nine twin pregnancies there are 18 twins. If the distribution of twins is random, then one would expect (18/1,058 • 215) or about 3.6 propositi to be members of a twin pair. Five were found and the difference is not significant. Similarly (18-5)/ (1,058-215) • 100 or 1.5% of "nonpropositi" are members of a twin pair, and not 0.47% as stated by the authors. Finally the difference in twin frequency between propositi (5/215) and nonpropositi (13/843) is not significant. Alasdair G. W. Hunter, M.D. Department of Genetics The Hospital for Sick Children 555 University Ave. Toronto, Ont., Canada REFERENCE
1. Armendares S, and Lisker R: Twinning and cleft lip with or without cleft palate, J PEDIATR 86:479, 1975.
Reply To the Editor: We have read with interest the points raised by Dr. Hunter regarding our letter that appeared in the March issue o f THE JOURNAL OF PEDIATRICS. We do not agree with him but recognize that there might be an element o f confusion in our letter, and would like to make clear that we speak all the time of twinning and not of twins. In this context the findings were: In the 215 families ascertained, there were 1,058 pregnancies, nine of which resulted in twins. In five of these nine pregnancies, one of the twins had CL(P), giving a figure of 2.3% (5/215), against four
The Journal of Pediatrics November 1975
twin pregnancies in the other 843 pregnancies, or 0.47% (4/843). Probably the confusion arises from the phrase " . . . 5-fold more than that present in their nontwin sibs." These should perhaps read " . . . 5-fold more than that present in all pregnancies in which no affected child was present." Salvador Armendares, M.D. Rubbn Lisker, M.D. Seceibn de Genktiea Departamento de lnvestigacibn Cient(fica Apartado Postal 73-032 Mbxico 73, D.F
Partial trisomy 15 (dup l 5q) syndrome and the need for precision in clinical cytogenetics To the Editor: The article by Bannister and Engel 1 in the June issue is a good one. The title on the front cover--A G-like trisomy--is less good. The full title on the inside is not much better. One key reference ~ pertaining to Bannister and Engel's central topic also might be added to their brief list. The following sequential points may be made about the paper by Bannister and Engel: (1) Their patient did not have a G chromosome problem; (2) the maternal "interchange" was a translocation; (3) this translocation involved not merely a D and an E chromosome, but specifically Nos. 15 and 17; (4) the breakpoints in these chromosomes were not given, but appear to be at 15q22 and 17p13 (using the Paris international chromosome nomenclature J whereby q = long arm and p = short arm); (5) the mother's karotype should therefore be designated (using Paris nomenclature;9: 46,XX,t (15;17) (q22;p13); (6) the child had chromosome imbalance due to maternal nondisjunction; specifically; (7) the child had duplication (dup) of most o f the long arm of No. 15 and possibly of a small portion of the short arm of No. 17, ie, the child had dupl5q and ?dupl7p; and (8) the child's karyotype should, therefore, using Paris nomenclature ~ be designated: 47,XY, + t (15pter---~15q22::17p13-~17pter) where "ter" = "terminus of a chromosome," the arrow means "running from.., to," and the double colon means "broken and joined to." All of this is far from trivial. The title and the key words in a title are what are used for indexing a paper (particularly one without a summary or abstract) so that it can be accurately filed and retrieved from the literature. Since human cytogenetics has become more precise, so must the writing, editing, and entitling of papers. This precision must extend to the precise use of current nomenclature. The report by Bannister and Engel 1 is o f particular clinical value, because their patient very closely resembled another patient 4 reported three years ago. This suggests the existence of a distinct mental retardation/malformation syndrome due to dup 15q. Bannister and Engel are to be congratulated, if not upon
