Familial orofaciodigital syndrome type I revealed by ultrasound prenatal diagnosis of porencephaly

Imaging Similarities Between Oral-Facial-Digital Syndrome Type 1 and Aicardi Syndrome: Prenatal and Postnatal Magnetic Resonance Imaging (MRI) Findings in 4 Patients

Prenatal identification by magnetic resonance imaging (MRI) of callosal anomalies, particularly with accompanying intracranial abnormalities, poses a challenge for accurate prognostication and fetal counseling as outcome can vary widely depending on underlying etiology. In female patients, Aicardi syndrome is an important consideration, and prompt postnatal ophthalmologic assessment to identify ocular stigmata of Aicardi syndrome can aid with anticipatory guidance and greater vigilance for seizures. We present a case of a female with fetal and postnatal MRI findings of agenesis of corpus callosum and type 2b interhemispheric cysts, characteristically found in Aicardi syndrome, but was found to have oral-facial-digital syndrome type 1 (OFD1). We also present 3 other companion cases with pre- and postnatal imaging of patients with Aicardi syndrome. These cases highlight the importance of widening the differential diagnosis to also include OFD1 for female patients with callosal anomalies.

Prenatal genetic considerations in congenital ventriculomegaly and hydrocephalus

BACKGROUND

Fetal ventriculomegaly (VM) is a frequent finding in prenatal ultrasound. Rather than a proper diagnosis, VM is a sonographic sign, making prenatal counseling a complex and challenging undertaking. VM can range from severe pathologic processes leading to severe neurodevelopmental delay to normal variants.

DISCUSSION

A growing number of genetic conditions with different pathophysiological mechanisms, inheritance patterns, and long-term prognosis have been associated both to isolated and complex fetal VM. These include chromosomal abnormalities, copy number variants, and several single gene diseases. In this review, we describe some of the most common genetic conditions associated with fetal VM and provide a simplified diagnostic workflow for the clinician.

Do X-linked diseases affect periodontal health?

Genetic factors play an important etiologic role in destructive periodontal diseases. There have been reports that sex chromosomes, especially disorders associated with the X chromosome, affect periodontal health. Although numerous X-linked diseases have been reported to be associated with various periodontal diseases, the association of gingivitis and/or periodontitis with these genetic syndromes should be considered tenuous and raises the question of whether the periodontal manifestation truly arises from an underlying X-linked genetic etiology. A brief overview of genetics in relation to sex chromosomes and putative X-linked genetic periodontal diseases is given.

Challenges in genetic counseling because of intra-familial phenotypic variation of oral-facial-digital syndrome type 1

Oral-facial-digital syndrome type 1 (OFD1; MIM 311200) is characterized by multiple anomalies of the oral cavity, face and digits. We report a family with OFD1, where two female siblings and their mother shared the same mutation of the responsible gene (OFD1) c.1193_1196delAATC. Phenotypic variability was observed among them; the mother showed minimal features of OFD1, whereas her two daughters showed partial features and the full spectrum of OFD1, respectively. Thus, OFD1 was suspected only after a health check-up during pregnancy of the second patient showing fetal brain anomaly and maternal polycystic kidney. For these reasons, there was a delay in the recognition of OFD1 in this family. Patients with OFD1 show phenotypic variability, which poses challenges for genetic counseling.

Prenatal stroke

The main focus of this chapter is the comprehensive description of the neuropathology, the imaging correlates and underlying mechanisms of prenatal stroke. We describe established prenatal stroke in subgroups similar to postnatal stroke: arterial (forebrain or hindbrain) infarction, venous thrombosis, primary lobar haemorrhage. This longitudinal classification should facilitate the study of risk factors and mechanisms. Forebrain lesions of arterial type present as porencephaly, (hemi)hydranencephaly, multicystic encephalopathy or schizencephaly. Venous prenatal forebrain stroke presents as simple porencephaly (in some of genetic nature) and sinus thrombosis. A list of rare porencephaly-like conditions is added for differentiation from arterial and venous porencephaly. Hindbrain infarctions (so far the only reported variants seem to be of arterial nature) present as brainstem disconnection, focal brainstem destruction, uni- or bilateral cerebellar destruction and focal spinal cord ischaemia. Prenatal intracranial haemorrhage and congenital brain infection should be considered in the differential diagnosis of prenatal stroke.

Clinical, molecular, and genotype-phenotype correlation studies from 25 cases of oral-facial-digital syndrome type 1: a French and Belgian collaborative study

Oral-facial-digital syndrome type 1 (OFD1) is characterised by an X linked dominant mode of inheritance with lethality in males. Clinical features include facial dysmorphism with oral, tooth, and distal abnormalities, polycystic kidney disease, and central nervous system malformations. Large interfamilial and intrafamilial clinical variability has been widely reported, and 18 distinct mutations have been previously reported within OFD1. A French and Belgian collaborative study collected 25 cases from 16 families. OFD1 was analysed using direct sequencing and phenotype-genotype correlation was performed using chi2 test. X inactivation studies were performed on blood lymphocytes. In 11 families, 11 novel mutations, including nine frameshift, one nonsense, and one missense mutation were identified, which spanned nine different exons. A combination of our results with previously reported cases showed that the majority of mutations (65.5%) was located in exons 3, 8, 9, 13, and 16. There was phenotype-genotype correlation between (a) polycystic kidney disease and splice mutations; (b) mental retardation and mutations located in exons 3, 8, 9, 13, and 16; and (c) tooth abnormalities and mutations located in coiled coil domains. Comparing the phenotype of the families with a pathogenic mutation to families with absence of OFD1 mutation, polycystic kidneys and short stature were significantly more frequent in the group with no OFD1 mutation, whereas lingual hamartomas were significantly more frequent in the group with OFD1 mutation. Finally, an X inactivation study showed non-random X inactivation in a third of the samples. Differential X inactivation between mothers and daughters in two families with high intrafamilial variability was of particular interest. Slight phenotype-genotype correlations were established, and X inactivation study showed that skewed X inactivation could be partially involved in the pathogenesis of intrafamilial clinical variability.