Paternal age and risk for selected birth defects in a large South American sample.

BACKGROUND: The relationship between maternal age (MA) and birth defects (BD) has been extensively studied while much less research, mostly with discordant results, has focused on the risk of paternal age (PA) for BD. Furthermore, no consensus has been reached on the best way to control the association of PA with MA. OBJECTIVES: The aim of the study was to evaluate the risk of PA increase, at 1-year intervals, for selected BD, especially controlling for the confounding effect of MA. METHODS: The sample comprised of 27,944 liveborns presenting 1 of 18 selected isolated BD. Conditional logistic regressions were applied to evaluate the risk of advanced PA and its yearly increase, adjusting by MA and other variables. RESULTS: Of the 18 analyzed BD, only the risk for preaxial polydactyly (PreP) showed a significant association with increasing PA, while advanced MA was of low risk. For esophageal and anal atresia, associations with both PA and MA increases were observed. CONCLUSIONS: Results support the hypothesis of advanced PA as a risk factor for PreP and helps clarify the so far unexplained nonrandom association between this defect and Down syndrome.

Analysis of surgical results and of residual postoperative deformities in preaxial polydactyly of the hand.

PURPOSE: Polydactyly is the most common congenital anomaly of the hand. It may occur as a separate event or as part of a syndrome, with preaxial polydactyly of the hand (or thumb duplication) being the most common among Caucasians. The present study analyzed the surgical results and the residual postoperative deformities of patients with thumb duplication. METHODS: Thirty-one patients with duplicated thumbs were surgically treated from January 2002 to April 2008 and 19 of them, who had returned during the late postoperative period, were evaluated. Each case was typed according to Wassel's classification into seven types and the most common category was type IV. Removal of radial component was done in 18 patients aged on average 51 months. RESULTS: Patients and parents were satisfied with both the functional results and the appearance of the reconstructed thumb. In the subjective evaluation of residual deformities, axis deviation and residual prominence were commonly found. There were coherencies in data between both subjective and objective outcomes. The children that had difficulty in holding very small objects in the subjective functional result were the same children with residual deformities in the objective result. Patient's age at surgery and Wassel's type influenced the analysis of residual postoperative deformities. There was statistically significant difference in cases of type VII and in patients operated at more than three years of age. Correlation between type VII and patient's age at time of surgery was found. The children with type VII duplication were operated later. CONCLUSIONS: For a better result, surgical correction should be performed before three years of age, thus correcting all the changes detected, mainly in type VII, in order to reduce the incidence of residual deformity. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A novel ZRS mutation leads to preaxial polydactyly type 2 in a heterozygous form and Werner mesomelic syndrome in a homozygous form.

Point mutations in the zone of polarizing activity regulatory sequence (ZRS) are known to cause human limb malformations. Although most mutations cause preaxial polydactyly (PPD), triphalangeal thumb (TPT) or both, a mutation in position 404 of the ZRS causes more severe Werner mesomelic syndrome (WMS) for which malformations include the distal arm or leg bones in addition to the hands and/or feet. Of more than 15 reported families with ZRS mutations, only one homozygous individual has been reported, with no change in phenotype compared with heterozygotes. Here, we describe a novel point mutation in the ZRS, 402C>T (AC007097.4:g.105548C>T), that is transmitted through two Mexican families with one homozygous individual. The homozygous phenotype for this mutation, WMS, is more severe than the numerous heterozygous individuals genotyped from both families who have TPT and PPD. A mouse transgenic enhancer assay shows that this mutation causes an expansion of the enhancer's expression domain in the developing mouse limb, confirming its pathogenicity. Combined, our results identify a novel ZRS mutation in the Mexican population, 402C>T, and suggest that a dosage effect exists for this ZRS mutation.

Experiencia con polidactilia preaxial en el Instituto Nacional de Pediatría / Experience with preaxial polydactyly at the Instituto Nacional de Pediatria

Introducción. La polidactilia se define como un exceso de dígitos o partes en manos o pies. La polidactilia del pulgar (preaxial) es la más común en la población blanca y asiática. Es importante el manejo quirúrgico temprano para evitar deformaciones en el dígito afectado. Métodos. Estudio retrospectivo de los pacientes que ingresaron al Instituto Nacional de Pediatría con diagnóstico de polidactilia preaxial en el período de marzo de 2001 a febrero de 2003. Resultados. Se diagnosticaron 57 pacientes, con edad promedio de 19 meses. Predominaron pacientes del sexo masculino (n =41) sobre los del femenino (n =16). Se encontraron 2 pacientes con pulgar duplicado en ambas manos, 39 pacientes en mano derecha y 16 en mano izquierda (total =59). El tipo IV de Wassel fue el más frecuentemente encontrado. A todos los pacientes se les realizó manejo quirúrgico. Se presentaron 10 pacientes (16.94%) con secuelas menores postoperatorias. Conclusiones. La casuística reportada en este trabajo es significativa. La correcta clasificación de esta malformación es importante para realizar una cirugía adecuada que tenga como objetivo la restauración funcional y estética de la mano.

Introduction. Polydactyly is defined as an excess of digits or parts in the hand or foot. Thumb (preaxial) polydactyly is commonly found in white and Asian populations. Early surgical management is important to avoid deformations in the affected digit. Methods. Patients were seen at the Instituto Nacional de Pediatria with a diagnosis of preaxial polydactyly during the period from March 2001 to February 2003. Results. Fifty seven patients with an average age of 19 months were observed. We found a prevalence of the masculine (n= 41) in comparison with the feminine gender (n= 16). Two patients had a duplicated thumb on both hands: 39 patients on the right and 16 on the left hand (total= 59 duplicated thumbs). Wassel type IV was the most frequently found polydactyly. All patients had surgical management; 10 patients had minor postsurgical residual deformities. Conclusions. The casuistic reported in this work is significant. Proper classification of this abnormality is important to offer the patient the proper surgery for restoring the hand’s function and aesthetics.