PP-19 Prenatal diagnosis of isolated bilateral congenital cataract

Objective

Congenital cataract stands as an orbital anomaly characterized by lens opacity, manifesting unilaterally or bilaterally, with an incidence of 1 in 10,000 births. Genetic syndromes are identifiable in roughly 10% of cases; nonetheless, congenital infections have been discerned in approximately 30% of instances. In the presence of unilateral or bilateral congenital cataracts, a comprehensive ultrasound evaluation, encompassing neurosonography, invasive prenatal diagnostic testing for karyotyping, and maternal TORCH panel analysis for fetal infections, becomes imperative. Furthermore, maternal utilization of pharmaceuticals (including steroids), radiation exposure, or exposure to potential teratogens, along with any underlying metabolic conditions, should be meticulously investigated for their potential etiological implications. In the context of this report, our objective is to present a case involving the prenatal diagnosis of an isolated instance of bilateral congenital cataract..

Case

A 36-year-old patient, gravida 6, parity 4, at 24 weeks and 4 days of gestation, was admitted to the prenatal diagnosis and treatment unit at our clinic for fetal anomaly screening. The patient had a history of pregestational diabetes mellitus and was meticulously monitored. Ultrasonographic examination confirmed a positive fetal heartbeat, while biometric measurements aligned with the gestational age, and amniotic fluid volume remained within normal ranges. Notable findings in fetal facial assessment included increased opacity observed in bilateral lenses within the coronal plane and orbital assessment (figure 1). Fetal neurosonography and abdominal evaluation yielded no evidence of periventricular calcification, hepatic/splenic calcification, or hyperechogenic bowel. Given the patient’s history of congenital cataract in a previous child, an isolated diagnosis of congenital cataract was considered. Upon fetal cardiac evaluation, borderline myocardial hypertrophy and perimembranous ventricular septal defect (VSD) were identified. At this juncture, the option of invasive prenatal diagnostic testing or cell-free fetal DNA analysis in maternal blood was presented. Maternal blood TORCH panel analysis yielded no abnormal findings, and in light of the patient’s preferences, she chose not to undergo invasive prenatal diagnostic testing. Throughout this process, the family was provided with comprehensive information regarding potential neonatal complications.

Discussion

Genetic testing and prenatal ultrasound have become primary methods of diagnosing congenital cataracts. The analysis by Yue Qin et al found a total of 41 cases of congenital cataracts diagnosed prenatally among 788,751 women who underwent the mid-tirmester fetal anatomical scan. Based on sonographic features, 16/41 (39.0%) had an intense echogenic pattern, 15/41 (36.6%) had a hyperechogenic spot, and 10/41 (24.4%) had a “double ring” sign. 17/41 (41.5%) were isolated and 24/41 (58.5%) had associated intraocular and extraocular findings. Microphthalmia, cardiac abnormalities and central nervous system abnormalities were the most common associated abnormalities. Potential etiology regarding the disease, 6 cases had  known family history of congenital cataracts, 4 cases had confirmed congenital rubella infection, and 2 cases had aneuploidy.[3]

Conclusion

Congenital cataract comprises 7.4-15.5% of all cases of childhood blindness. Detecting congenital cataract during the prenatal phase and discerning any potential associations with other pathologies are critical measures for timely intervention and treatment of conditions that could lead to morbidity, mortality, or vision impairment. Emphasizing the significance of precise prenatal diagnosis of congenital cataract, this process greatly aids patients and their families by enabling personalized genetic counseling. Therefore, meticulous sonographic evaluations, taking into consideration the patient’s specific risk factors, are paramount to ensuring comprehensive care.

Keywords

Congenital cataract, lens, opacity, ultrasound

1. Rahi JS, Dezateux C and British Congenital Cataract Interest Group. Measuring and interpreting the incidence of congenital ocular anomalies: lessons from a national study of congenital cataract in the UK. Invest Ophthalmol Vis Sci 2001; 42: 1444–1448. 
2. Yi J, Yun J, Li ZK, et al. Epidemiology and molecular genetics of congenital cataracts. Int J Ophthalmol2011; 4: 422–432.
3. Qin Y, Zhong X, Wen H, Zeng Q, Liao Y, Luo D, Liang M, Tang Y, Guo J, Cao H, Yang S, Tian X, Luo G, Li S. Prenatal Diagnosis of Congenital Cataract: Sonographic Features and Perinatal Outcome in 41 Cases. Ultraschall Med. 2022 Dec;43(6):e125-e134. English. 

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