Prenatal diagnosis of Miller-Dieker syndrome/PAFAH1B1-related lissencephaly: Ultrasonography and genetically investigative results

Phenotypic Features of Fourteen Fetal Cases With a PTEN Variant

OBJECTIVE

To present the prenatal sonographic features, genomic findings, and pregnancy outcomes of fetuses diagnosed in utero with a PTEN variant.

METHOD

This retrospective study analyzed 14 cases of PTEN variants identified through prenatal ultrasound and subsequently confirmed by genetic testing. Clinical and laboratory data were collected for these cases, encompassing maternal demographics, prenatal sonographic findings, molecular testing results, and pregnancy outcomes.

RESULTS

A total of 14 fetuses with (likely) pathogenic PTEN variants were included in the study. Five cases exhibited abnormalities on second-trimester ultrasound scans; specifically, three presented with macrocephaly, one showed mild ventriculomegaly, and another had cardiac defects (coarctation of the aorta and ventricular septal defect). Nine additional cases were identified during the third trimester. Among these nine cases, six displayed macrocephaly with or without polyhydramnios and ventriculomegaly; one case had mild ventriculomegaly; another presented only with mild polyhydramnios; and one was characterized by macrosomia. Eleven cases involved de novo variants, whereas three variants were inherited from parents.

CONCLUSIONS

Macrocephaly emerged as the most prevalent sign observed in utero that prompted genetic detection of PTEN defects. This study encourages obstetricians to enhance their awareness regarding PTEN-related disorders in fetuses presenting with macrocephaly.

Prenatal Diagnosis of KBG Syndrome: Phenotypic and Genotypic Features of 12 Fetal Cases With the Disorder

OBJECTIVE

To present prenatal sonographic features, genomic results, and pregnancy outcomes of fetuses with KBG syndrome (KBGS).

METHOD

This was a retrospective study of 12 cases with KBGS diagnosed by prenatal ultrasound and confirmed by genetic testing. Clinical and laboratory data were collected for these cases, including maternal demographics, prenatal sonographic findings, molecular test results, and pregnancy outcomes.

RESULTS

Twelve cases of KBGS were diagnosed prenatally with confirmatory genetic testing. Five had an abnormal first-trimester ultrasound with increased nuchal translucency (NT). Seven cases had a normal first-trimester ultrasound. Among these, four had mild ventriculomegaly in the second or third trimester, one had an arachnoid cyst found at 22 weeks, one had umbilical-systemic shunt, ventriculomegaly and polyhydramnios found at 24 weeks, and one presented with fetal growth restriction at 30 weeks. Four pregnancies continued to term, and infants presented with the classic phenotype of KBGS at a follow-up of 12 months. All ANKRD11 alterations in the 12 cases were de novo, and were characterized as either deletions encompassing ANKRD11 or loss-of-function variants.

CONCLUSION

Increased NT and mild ventriculomegaly are two common sonographic features of fetal KBGS. Prenatal diagnosis of KBGS can be achieved with ultrasound and comprehensive molecular testing.

Clinical analysis of PAFAH1B1 gene variants in pediatric patients with epilepsy

PURPOSE

PAFAH1B1, also known as LIS1, is associated with type I lissencephaly in humans, which is a severe developmental brain disorder believed to result from abnormal neuronal migration. Our objective was to characterize the genotypes and phenotypes of PAFAH1B1-related epilepsy.

METHODS

We conducted a comprehensive analysis of the medical histories, magnetic resonance imaging findings, and video-electroencephalogram recordings of 11 patients with PAFAH1B1 variants at the Neurology Department of Beijing Children's Hospital from June 2017 to November 2022.

RESULTS

The age of onset of epilepsy ranged from 2 months to 4 years, with a median onset age of 5 months. Among these 11 patients (comprising 6 boys and 5 girls), all were diagnosed with lissencephaly type 1. Predominantly, generalized tonic-clonic and spasm seizures characterized PAFAH1B1-related epilepsy. Additionally, 10 out of the 11 patients exhibited severe developmental disorders. All patients exhibited de novo variants, with three individuals displaying 17p13.3 deletions linked to haploinsufficiency of PAFAH1B1. Four variants were previously unreported. Notably, three patients with 17p13.3 deletions displayed developmental delay and drug resistant epilepsy, whereas the single patient with mild developmental delay, Intelligence Quotient (IQ) 57 and well-controlled seizures had a splicing-site variant.

CONCLUSION

The severity of the phenotype in patients with PAFAH1B1 variants ranged from drug-responsive seizures to severe epileptic encephalopathy. These observations underscore the clinical heterogeneity of PAFAH1B1-related disorders, with most patients exhibiting developmental disorders. Moreover, the severity of epilepsy appears to be linked to genetic variations.

A de novo heterozygous POU3F3 genotype for the p.(Q214*) variant in a fetus with transient isolated bilateral mild ventriculomegaly: a case report and review of the literature

The prenatal prevalence of isolated ventriculomegaly is 0.039%-0.087%. Most isolated mild ventriculomegaly (MV) fetuses (>90%) have a favorable prognosis. However, 5.6% to 7.9% of fetuses with isolated MV have adverse neurodevelopmental outcomes. In this study, we reported the first case of prenatal Snijders Blok-Fisher syndrome (OMIM: #618604) caused by a truncating variant of POU3F3 (OMIM: *602480) in a fetus with transient isolated bilateral MV. The results of karyotype analysis, chromosomal microarray analysis, and TORCH infection evaluation for the fetus were all negative. However, a de novo likely pathogenic nonsense variant of NM_006236.3 (POU3F3): c.640C > T [rs1254251078] p.(Q214*) was identified by whole-exome sequencing (WES). Despite sufficient genetic counseling, the mother refused to undertake further brain magnetic resonance imaging (MRI) and decided to keep the fetus. She gave birth to a male infant through a full-term vaginal delivery. With a long-term follow-up, the infant unfortunately gradually presented with delayed motor development. The postnatal brain MRI of the proband showed dysplasia of the corpus callosum and ventriculomegaly. Considering the high probability of misdiagnosis for such cases, we further summarized the prenatal phenotypes from 19 reported patients with variants in POU3F3. The results revealed that 14 patients displayed a normal prenatal ultrasonographic manifestation, while only approximately 26.32% of fetuses showed MV or cysts without structural deformity. Thus our findings expand the variant spectrum of POU3F3 and suggest the importance of undertaking WES and brain MRI when the fetus has isolated bilateral MV.

Acute Bowel Ischemia in a Premature Neonate with Miller-Dieker Syndrome and Anomalous Right Coronary Artery From the Pulmonary Artery

Miller-Dieker syndrome (MDS) is a rare disease characterized by type I lissencephaly, craniofacial dysmorphisms, intellectual disability, seizures, and death in early childhood. We report a case of a premature infant with MDS with an anomalous right coronary artery from the pulmonary artery who developed sudden bowel ischemia. This case prompts the reconsideration of cardiovascular involvement in patients with MDS. In addition, this review highlights key clinical features and reviews the critical manifestations of MDS that persist into childhood. [Pediatr Ann. 2023;52(8):e283-e291.].

A Case of Class I 17p13.3 Microduplication Syndrome with Unilateral Hearing Loss

17p13 is a chromosomal region characterized by genomic instability due to high gene density leading to multiple deletion and duplication events. 17p13.3 microduplication syndrome is a rare condition, reported only in 40 cases worldwide, which is found in the Miller-Dieker chromosomal region, presenting a wide range of phenotypic manifestations. Usually, the duplicated area is de novo and varies in size from 1.8 to 4.0 Mbp. Critical genes for this region are PAFAH1B1 (#601545), YWHAE (#605066), and CRK (#164762). 17p13.3 microduplication syndrome can be categorized into two classes (Class I and Class II) based on the genes that are present in the duplicated area, which lead to different phenotypes. In this report, we present a new case of Class I 17p13.3 microduplication syndrome that presents with unilateral sensorineural hearing loss. Oligonucleotide and SNP array comparative genomic hybridization (a-CGH) analysis revealed a duplication of approximately 121 Kbp on chromosome 17p13.3, which includes YWHAE and CRK genes. Whole-exome sequencing (WES) analysis confirmed the duplication. Our patient has common clinical symptoms of Class I 17p13.3 microduplication syndrome, and in addition, she has unilateral sensorineural hearing loss. Interestingly, WES analysis did not detect any mutations in genes that are associated with hearing loss. The above findings lead us to propose that hearing loss is a manifestation of 17p13.3 duplication syndrome.