Prenatal Diagnosis of a Mosaic Paternal Uniparental Disomy for Chromosome 14: A Case Report of Kagami-Ogata Syndrome

Prenatal diagnosis of recurrent Kagami-Ogata syndrome inherited from a mother affected by Temple syndrome: a case report and literature review

BACKGROUND

Kagami-Ogata syndrome (KOS) and Temple syndrome (TS) are two imprinting disorders characterized by the absence or reduced expression of maternal or paternal genes in the chromosome 14q32 region, respectively. We present a rare prenatally diagnosed case of recurrent KOS inherited from a mother affected by TS.

CASE PRESENTATION

The woman's two affected pregnancies exhibited recurrent manifestations of prenatal overgrowth, polyhydramnios, and omphalocele, as well as a small bell-shaped thorax with coat-hanger ribs postnatally. Prenatal genetic testing using a single-nucleotide polymorphism array detected a 268.2-kb deletion in the chromosome 14q32 imprinted region inherited from the mother, leading to the diagnosis of KOS. Additionally, the woman carried a de novo deletion in the paternal chromosome 14q32 imprinted region and presented with short stature and small hands and feet, indicating a diagnosis of TS.

CONCLUSIONS

Given the rarity of KOS as an imprinting disorder, accurate prenatal diagnosis of this rare imprinting disorder depends on two factors: (1) increasing clinician recognition of the clinical phenotype and related genetic mechanism, and (2) emphasizing the importance of imprinted regions in the CMA workflow for laboratory analysis.

Living birth following preimplantation genetic testing for monogenic disorders to prevent low-level germline mosaicism related Nicolaides–Baraitser syndrome

Objective: Paternal sperm mosaicism has few consequences for fathers for mutations being restricted to sperm. However, it could potentially underlie severe sporadic disease in their offspring. Here, we present a live birth of a female infant from a father with low-level sperm DNA mosaicism achieved via preimplantation genetic testing for monogenic disorders (PGT-M).

Methods: A couple with the father carrying sperm DNA mosaicism received standard in vitro fertilization treatment, with intracytoplasmic sperm injection, embryo biopsy, polymerase chain reaction, and DNA analysis. Only one unaffected embryo was transferred to the uterine cavity. Amniocentesis was performed at the 16th week of gestation by copy-number variation-sequencing, karyotyping, and Sanger sequencing.

Results: Eight surviving embryos were biopsied during the blastocyst stage. Karyomapping and Sanger sequencing were applied to detect the euploidy and paternal mutation. After performing PGT-M, followed by successful pregnancy, the prenatal genetic diagnoses revealed that the fetus was unaffected, and one healthy girl was born.

Conclusion: This is the first reported live birth with unaffected children achieved via PGT for a low-level germline mosaicism father. It not only opens the possibility of preventing the recurrent monogenic disease of children among gonadal mosaicism families but also alerts clinicians to consider gonadal mosaicism as the source of DMNs.

Case report: Prenatal diagnosis of Kagami–Ogata syndrome in a Chinese family

The aim of this work was to explore the genetic cause of the proband (Ⅲ2) presenting with polyhydramnios and gastroschisis. Copy number variation sequencing (CNV-seq), methylation-specific multiplex PCR (MS-PCR), and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) were used to characterize the genetic etiology. CNV-seq revealed a deletion of 732.26 kb at 14q32.2q32.31 in the proband (Ⅲ2) and its mother (Ⅱ2). MS-PCR showed the maternal allele was missing in the proband, while paternal allele was missing in its mother. MS-MLPA showed deletion of the DLK1, MEG3, MIR380, and RTL1 genes of both the proband and its mother. MEG3 imprinting gene methylation increased in the proband, while decreased in its mother. It was indicated that a maternally transmitted deletion was responsible for Kagami–Ogata syndrome in the proband (Ⅲ2), and the de novo paternal deletion resulted in Temple syndrome in the mother (Ⅱ2). Prenatal diagnosis was provided at 17+3 weeks of pregnancy on the mother’s fourth pregnancy (Ⅲ4). Fortunately, the karyotype and single-nucleotide polymorphism array (SNP array) results were normal. The current investigation provided the detection methods for imprinted gene diseases, expanded the phenotype spectrum of the disease, and obtained the insight into the diagnosis, prenatal diagnosis, and genetic counseling of the disease.