Lowry R Brian, Kohut Ruth, Sibbald Barbara, Rouleau Jocelyn
Alberta Congenital Anomalies Surveillance System, Health Surveillance, Alberta Health and Wellness, Calgary, Alta.
Can J Ophthalmol. 2005 Feb;40(1):38-44. doi: 10.1016/S0008-4182(05)80115-2.
A higher than expected rate of anophthalmia/microphthalmia (A/M) for 1999 was noted in both the Alberta Congenital Anomalies Surveillance System (ACASS) and the Canadian Congenital Anomalies Surveillance System (CCASS). Since this increase was at variance with the previous 19 years, we performed a review to determine whether the increase was true and, if so, the possible explanation.
We reviewed the records of the cases of A/M in the ACASS together with the accompanying attachments (e.g., consultant, autopsy and chromosome reports) for 1991-2001. In addition, we contacted all 91 registered ophthalmologists in Alberta. Letters were also written to the Edmonton and Calgary offices of the Canadian National Institute for the Blind (CNIB).
Sixty cases of A/M were ascertained over the study period. Of the 88 active ophthalmologists in the province, 21 (24%) replied, but no new cases were ascertained from this source. No replies were received from the CNIB. We constructed five categories of clinical phenotypes for the 60 cases: 20 had a chromosomal etiology, 13 had a recognized syndrome or association, 16 had extraocular malformations, 5 had other eye anomalies, and 6 had A/M only. Pregnancy terminations were not included. The higher rate in 1999 was mainly due to cases with a chromosomal etiology or a recognized syndrome or association. There was no indication that a teratogen was causing a cluster of A/M cases, as our annual rates were comparable to those for other jurisdictions not only in Canada but also in other countries.
Our review confirmed that the rate of A/M in Alberta in 1999 was high but that the increase was mainly due to five cases of trisomy 13 together with one case associated with a syndrome (Meckel-Gruber). Our findings provide reassurance that there was no environmental cause of clustering of anophthalmia or microphthalmia. This review demonstrates the importance of ongoing population-based surveillance in providing baseline birth prevalence rates for evaluating trends and clusters.
艾伯塔省先天性异常监测系统（ACASS）和加拿大先天性异常监测系统（CCASS）均发现，1999年无眼/小眼（A/M）发生率高于预期。由于这一增长与此前19年的情况不符，我们进行了一项审查，以确定这种增长是否属实，若属实，则找出可能的原因。
我们查阅了ACASS中1991 - 2001年A/M病例的记录以及相关附件（如会诊、尸检和染色体报告）。此外，我们联系了艾伯塔省所有91名注册眼科医生。还致函加拿大国家盲人研究所（CNIB）的埃德蒙顿和卡尔加里办公室。
在研究期间共确定了60例A/M病例。该省88名在职眼科医生中，21名（24%）回复了，但未从这一渠道确定新病例。未收到CNIB的回复。我们将60例病例构建为五类临床表型：20例有染色体病因，13例有公认的综合征或关联，16例有眼外畸形，5例有其他眼部异常，6例仅有A/M。不包括终止妊娠的情况。1999年的较高发生率主要归因于有染色体病因或公认的综合征或关联的病例。没有迹象表明致畸剂导致了A/M病例的聚集，因为我们的年发生率不仅与加拿大其他司法管辖区相当，而且与其他国家的也相当。
我们的审查证实，1999年艾伯塔省的A/M发生率较高，但增长主要归因于5例13三体病例以及1例与综合征（梅克尔 - 格鲁伯综合征）相关的病例。我们的研究结果让人放心，即不存在导致无眼或小眼聚集的环境原因。这项审查表明了持续进行基于人群的监测对于提供基线出生患病率以评估趋势和聚集情况的重要性。
