Prenatal Sonographic Features of Beckwith-Wiedemann Syndrome

CDKN1C -Related Beckwith-Wiedemann Syndrome: First Patient from India

Beckwith-Wiedemann syndrome (BWS; MIM# 130650) is a well-characterized pediatric overgrowth disorder. In approximately 5% of the cases, it is caused by pathogenic variants in the CDKN1C (cyclin-dependent kinase inhibitor 1C). CDKN1C gene encodes for a protein p57 (KIP2) that acts as an inhibitor of cyclin-dependent kinases (CDK) that are expressed in the G and S-phase of the cell cycle, thus regulating cellular proliferation. Variants in CDKN1C gene lead to loss of inhibitory function of CDK and thus impair the inhibition of growth, resulting in BWS phenotype. We describe here a 2.5-year-old boy with a maternally inherited variant c.182G > T, p.Trp61Cys in the CDKN1C gene causing BWS. The natural history of the disorder is described along with the gradual change in the facial features. An insight into the genotype-phenotype correlation and disorders to be considered in the differential diagnosis is provided. We describe a common overgrowth syndrome with its rare genetic mechanism and highlight the salient features that help in making a diagnosis and managing patients.

Ultrasound and molecular prenatal diagnosis of Beckwith-Wiedemann syndrome: Two case reports

Beckwith-Wiedemann syndrome (BWS) is a rare genetic disease, characterized by macrosomia, congenital malformations and tumor predisposition, associated with genetic and epigenetic alterations in the 11p15 region. Most cases are diagnosed after birth, with prenatal diagnosis being difficult and depending on the identification of specific ultrasound anomalies, namely macrosomia, macroglossia, omphalocele and renal dysplasia. Case 1: Ultrasound diagnosis at 13 weeks of isolated omphalocele with normal array. At 20 weeks, there were shortened fetal long bones, foot deformity, macroglossia, corpus callosum hypoplasia and bilateral nephromegaly. Due to the polymalformative syndrome, a termination of pregnancy (TOP) was performed. The anatomopathological study of the placenta identified mesenchymal dysplasia. The search for the methylation pattern of the 11p15 region by MS-MLPA was normal and the molecular study of the CDKN1C gene identified a likely pathogenic variant, inherited from the mother. Case 2: Morphological ultrasound at 21 weeks revealed macrosomia, macroglossia, omphalocele, bilateral renal dysplasia, and hydramnios. The cytogenetic study, after amniocentesis, was normal (46,XX karyotype). TOP was performed. The anatomopathological study of the fetus confirmed the described malformations and the one concerning the placenta identified placentomegaly. The search for the methylation pattern of the 11p15 region by MS-MLPA revealed abnormal methylation. These results confirmed the diagnosis of BWS in both cases. Prenatal ultrasound suspicion of this pathology is extremely important to guide the conduct in pregnancy and/or the prevention of perinatal complications. Shortened fetal long bones and foot deformity complement the broad spectrum of this syndrome. Positive molecular tests allow confirming the diagnosis, assessing the risk of recurrence and guiding the surveillance of future pregnancy.

Kagami-Ogata syndrome: an important differential diagnosis to Beckwith-Wiedemann syndrome

We report the case of a fetus with sonographic characteristics of Beckwith-Wiedemann syndrome (BWS). A 30-year-old gravida 2 para 1 was referred to our fetal medicine unit with an omphalocele. Fetal macrosomia, organomegaly, and polyhydramnios but no macroglossia were detected and BWS was suspected. Genetic testing for BWS did not confirm the suspected diagnosis as the karyotype was normal. Symptomatic polyhydramnios led to repeated amnioreductions. At 35 + 5 weeks of gestation, a female neonate of 3660 g was delivered with APGAR scores of 6/7/8, after 1/5/10 min, respectively. The abnormal shape of the thorax, facial dysmorphism, need for ventilation, and generalized muscular hypotonia led to the suspicion of Kagami-Ogata syndrome (KOS), which was confirmed by genetic testing. KOS in our patient was caused by a large deletion in the MEG3-region on chromosome 14q32 affecting the maternal allele. In this report, we highlight the notion that when sonographic signs suggestive of BWS such as macrosomia, polyhydramnios, and omphalocele are present and genetic testing does not confirm the suspected diagnosis, KOS should be tested for.