American Journal of Medical Genetics M850 (1992)

Letter to the Editor

Relation Between the Prevalence of Anorectal Malformations in Children With Down Syndrome and Their Prevalence in the General Population

To the Editor: TABLE I. Anorectal Malformations in Children of Different Origins

The letter by Torfs et al. in this volume presents inter- esting data further confirming the relatively high fre- quency of anorectal malformations in individuals with Down syndrome. The data from our survey in Jerusalem [Zlotogora et al., 19891, those from Urioste and Mar- tinez-F'rias [19911 in Spain, and the data from California are summarized in Table I. One can see that the fre- quency of anorectal malformations in children with Down syndrome is related to its prevalence in the popu- lation in which the child came from. The highest preva- lence of anorectal malformations was found in Jerusa- lem in both normal children (0.065%) and in children with Down syndrome (2.2%). The lowest prevalence in both groups was found in Spain (0.020 and 0.36%, re- spectively).

Numerous congenital malformations are clearly asso- ciated with with trisomy 21; they are observed with a similar distribution as in the general population but with a much higher incidence. For instance, esophageal anomalies (as stressed by Torfs et al.), but also choanal atresia, pyloric stenosis, cleft lip 2 cleft palate, talipes equino-varus, cryptorchidism, and spina bifida occulta are found in children with trisomy 21 with a much higher incidence than in the general population [Sha- piro, 19831. These observations were presented to sup- port the theory that in Down syndrome as in other chro- mosomal imbalance there is "decreased developmental and physiological buffering against genetic and envi- ronmental forces" [Shapiro, 19831. According to this theory it is expected that in populations in which the incidence of a malformation is high the same malfor- mation will be observed in individuals with chromo- some imbalance with a relatively higher incidence

Anorectal malformations General Down

population (%) syndromeE) Jerusalem 0.065" 2.2" Spain 0.020 0.36 California 0.035 1.1 "Anal atresia only (in Jerusalem the prevalence of anorectal malforma- tions in children with Down syndrome was 3.3%; however, only the prevalence of anal atresia in the general population was available).

than the one observed in children with the same syn- drome originating from a population in which the mal- formation is rarer. This prediction is clearly confirmed by the observation on the prevalence of anorectal mal- formations in Down syndrome as compared to their prevalence in normal individuals in three different pop- ulations (Table I). This may also be true for the other malformations which are frequent in individuals with chromosomal imbalance.

REFERENCES Shapiro BL (1983): Down syndrome-a disruption of homeostasis. Am J

Med Genet 14:241-269. Urioste M, Martinez-FMas ML (1991): Anorectal anomalities and Down

syndrome. Am J Med Genet 39:493. Zlotogora J, Abu-Dalu K, Lernau 0, Sagi M, Voss R, Cohen T (1989):

Anorectal malformations and Down syndrome. Am J Med Genet 34:330-331.

Joel Zlotogora Department of Human Genetics Hadassah Medical Center Hebrew University Jerusalem, Israel

Received for publication May 4, 1992. Address reprint request to Joel Zlotogora, Department of

Human Genetics, Hadassah Medical Center, Jerusalem il91100, Israel.

0 1992 Wiley-Liss, Inc.