All newborns delivered in the hospital (657 live births) and, all the children less than 12 years admitted in the wards (6,782 children) and attending outpatient clinics (61,004 children), between 1 January and 31 December 2001 were screened for the presence of PAT. All children with isolated PAT (not associated with a pit or dysplastic ear) formed the study group. A detailed clinical examination was done to rule out other congenital anomalies. Informed consent was obtained from the parents of all children prior to enrollment in the study. All patients were subjected to ultrasonographic examination of the abdomen. Same number of age-and sex-matched patients who had to undergo ultrasound examination of the abdomen for any non-renal problems were included in the control group. Abdominal USG of the three neonates in the control group was done at the time of cranial USG, after informed consent of the parents. Chromosomal analysis was not done in any patient. During the study period, there were 32 subjects with isolated preauricular tags, and two of the 657 neonates born in the hospital also had isolated PAT. Therefore, a total of 34 patients (M:F :: 1.6:1) were enrolled in the study group.

The estimated prevalence of isolated PAT in this combined population of neonates and children was 0.5 per thousand (34/68,441). The average age of the 31 children (excluding neonates) was 4.7 year (range, 3mo to 10 years). Of the 34 patients with isolated PAT (41% right-sided, 35% left-sided, and 24% bilateral), urinary tract abnormalities were detected in 3 children (8.8%), as compared to none in the control group (P >0.05). Two male children, 4-year-old and 7-year-old had uni-lateral hydronephrosis. One 3-day-old female neonate had left sided isolated PAT and left-sided double renal pelvis. None of the children had associated congenital anomalies or a posi-tive family history of tags or renal anomalies.

In general, preauricular tags and pits have only cosmetic importance, but associated malformations in the ear/face region and kidneys, and hearing impairment have been reported previously(2,3). As differentiation of both the renal tract and ears occurs at the same stage of embryonic development, disturbances at this time can give rise to coincidental abnormality. The prevalence of isolated PAT among 657 consecutively delivered newborns in this study was 3/1000, which is less than the reported prevalence of 4-5.3 per thousand live-births in previous studies(4,6). Different authors have found variable results regarding association between isolated PAT and urinary tract abnormalities. Kohelet, et al.(4) recently reported a significant association between isolated PAT and urinary tract abnormalities among 76 infants studied with USG. Kugelman, et al.(6) did not find any case with renal malformation among 26 infants with PAT or pits studied by USG. Wang, et al.(5) have, however, recently recommended that renal USG is not indicated for isolated PAT,

This is the first study documenting the association of isolated PAT with renal anomalies in the pediatric age group as a whole. All the previous studies have addressed this problem in the neonates(4,6). Although the prevalence of renal anomalies in those with isolated PAT in this study was similar to that found by Kohelet and Arbel (8.6%), it did not reach statistical significance probably because of the small sample size. A study with a larger sample size may provide more definitive information on the association between these two conditions. Until then, we feel that children with even isolated PAT should undergo an ultrasonographic evalua-tion for urinary tract abnormalities.