Prenatal diagnosis of Proteus syndrome: Diagnosis of an AKT1 mutation from amniocytes

Prenatal Diagnosis of Proteus Syndrome: About a Case

Proteus syndrome (PS) is a rare disorder (< 1/1000000), marked by progressive overgrowth commonly impacting the skeleton, skin, adipose tissue, and central nervous system. Clinical criteria were established in 2019. PS arises from a somatic activating variation in the AKT1 gene. We report the second case of PS diagnosed prenatally using whole exome sequencing (WES). A 34-year-old woman was referred for nonvisualized anterior brain structures and genital anomalies. At 21 weeks of gestation (WG), ultrasonography confirmed brain anomalies, genital anomalies, and macrosomia. Array-CGH revealed no pathogenic imbalances (arr(X,1-22)×2). Follow-up ultrasound (25 WG) and MRI (27 WG) also showed a megalencephaly, leading to WES on amniocytes. The reported mosaic variation in AKT1 was identified. Medical termination of pregnancy occurred at 30 + 1 WG. We present a case of PS confirmed prenatally via WES. To date, six cases of prenatal PS suspicion have been reported, four of which lacked molecular diagnosis. Calculating prenatal clinical scores indicate PS could not be definitively diagnosed without molecular confirmation. Certain features, such as limb malformation and gray matter heterotopia, seem to be significant in prenatal diagnosis. WES, with an average coverage depth of 130X, is valuable for diagnosing suspected PS.

Klippel-Trénaunay-Weber Syndrome: Prenatal Diagnosis and Review of the Literature

Klippel-Trénaunay-Weber syndrome (KTW) is a rare congenital disease, representing a challenge in prenatal diagnosis due to overlapping characteristics with other syndromes and no specific genetic markers known to date. We have collected all the cases present in the literature on the prenatal diagnosis of KTW, emphasizing common ultrasound findings that can guide the clinician and genetics to the prenatal counseling. Thus, we collected all the information about the postnatal prognosis and the necessity for treatment. Our review of 44 cases highlights the typical common features: hemihypertrophy, predominantly affecting the right leg, with cystic lesions extending to the trunk or upper limbs and rare internal organ involvement. Prenatal complications, including hydrops and polyhydramnios, emphasize the need for a careful ultrasound follow-up. Despite no identified genetic mutation, genetic counseling and invasive testing are recommended. Mortality rate due to a severe complication known as Kasabach-Merritt syndrome, underlines the importance of early diagnosis and accurate management strategies. Prenatal diagnosis of KTW, guided by ultrasound findings and genetic counseling, could help with informed decision-making and optimal care planning.

miR-204-3p Regulates Glioma Cell Biological Behaviors via Targeting Protein Kinase B (AKT1)

This study assesses miR-204-3p’s role in glioma. Cells were transfected with miR-204-3pmimics, miR-204-3p inhibitor, or si-AKT1 to measure cell proliferation, invasion, migration and apoptosis. Glioma tissues showed a significantly downregulated miR-204-3p, whose knockdown can significantly promote cell proliferation, migration and invasion. However, all the above changes or cell behavior were inhibited by overexpression of miR-204-3p. miR-204-3p regulated AKT1 and its silence can promote cell proliferation and decrease apoptosis by increasing AKT1 expression. However, si-AKT1 transfection inhibited cell proliferation and promote apoptosis induced by miR-204-3p knockdown. In summary, miR-204-3p regulates glioma cell biological behaviors by targeting AKT1.

Characterization of a rare mosaic unbalanced translocation of t(3;12) in a patient with neurodevelopmental disorders

Background

Unbalanced translocations may be de novo or inherited from one parent carrying the balanced form and are usually present in all cells. Mosaic unbalanced translocations are extremely rare with a highly variable phenotype depending on the tissue distribution and level of mosaicism. Mosaicism for structural chromosomal abnormalities is clinically challenging for diagnosis and counseling due to the limitation of technical platforms and complex mechanisms, respectively. Here we report a case with a tremendously rare maternally-derived mosaic unbalanced translocation of t(3;12), and we illustrate the unreported complicated mechanism using single nucleotide polymorphism (SNP) array, fluorescence in situ hybridization (FISH), and chromosome analyses.

Case presentation

An 18-year-old female with a history of microcephaly, pervasive developmental disorder, intellectual disability, sensory integration disorder, gastroparesis, and hypotonia presented to our genetics clinic. She had negative karyotype by parental report but no other genetic testing performed previously. SNP microarray analysis revealed a complex genotype including 8.4 Mb terminal mosaic duplication on chromosome 3 (3p26.3->3p26.1) with the distal 5.7 Mb involving two parental haplotypes and the proximal 2.7 Mb involving three parental haplotypes, and a 6.1 Mb terminal mosaic deletion on chromosome 12 (12p13.33->12p13.31) with no evidence for a second haplotype. Adjacent to the mosaic deletion is an interstitial mosaic copy-neutral region of homozygosity (1.9 Mb, 12p13.31). The mother of this individual was confirmed by chromosome analysis and FISH that she carries a balanced translocation, t(3;12)(p26.1;p13.31).

Conclusion

Taken together, the proband, when at the stage of a zygote, likely carried the derivative chromosome 12 from this translocation, and a postzygotic mitotic recombination event occurred between the normal paternal chromosome 12 and maternal derivative chromosome 12 to “correct” the partial 3p trisomy and partial deletion of 12p. To the best of our knowledge, it is the first time to report the mechanism utilizing a combined cytogenetic and cytogenomic approach, and we believe it expands our knowledge of mosaic structural chromosomal disorders and provides new insight into clinical management and genetic counseling.