Traboulsi syndrome caused by mutations in ASPH: An autosomal recessive disorder with overlapping features of Marfan syndrome.

Traboulsi syndrome, otherwise known as facial dysmorphism, lens dislocation, anterior-segment abnormalities and spontaneous filtering blebs, is an autosomal recessive condition associated with characteristic ocular features including dislocated crystalline lenses, anterior segment abnormalities and in some individuals, non-traumatic conjunctival cysts. There is a distinctive facial appearance which includes flattened malar region with convex nasal ridge. Alterations in the aspartate beta-hydroxylase (ASPH) gene are known to be the cause of the condition. We report seven further individuals from six unrelated families with characteristic ocular and facial features. Five individuals had aortic root dilatation, with childhood onset in some, and one undergoing aortic root repair aged 47 years for severe aortic regurgitation and aortic root dilatation. Interestingly, inguinal hernias were commonly reported. Although some skeletal features were seen, these were not consistent. One of the patients had mild deficiency of factor VII on clotting studies. The ASPH protein hydroxylates specific asparagine- and aspartate-residues in epidermal growth factor (EGF)-domain containing proteins including coagulation factors and associated genes including FBN1. We propose this as an explanation for the overlap in clinical features with Marfan syndrome and conclude that Traboulsi syndrome is an important differential diagnosis. We strongly recommend echocardiography surveillance for patients with Traboulsi syndrome.

Heterozygous variants in ZBTB7A cause a neurodevelopmental disorder associated with symptomatic overgrowth of pharyngeal lymphoid tissue, macrocephaly, and elevated fetal hemoglobin.

By clinical whole exome sequencing, we identified 12 individuals with ages 3 to 37 years, including three individuals from the same family, with a consistent phenotype of intellectual disability (ID), macrocephaly, and overgrowth of adenoid tissue. All 12 individuals harbored a rare heterozygous variant in ZBTB7A which encodes the transcription factor Zinc finger and BTB-domain containing protein 7A, known to play a role in lympho- and hematopoiesis. ID was generally mild. Fetal hemoglobin (HbF) fraction was elevated 2.2%-11.2% (reference value <2% in individuals > 6 months) in four of the five individuals for whom results were available. Ten of twelve individuals had undergone surgery at least once for lymphoid hypertrophy limited to the pharynx. In the most severely affected individual (individual 1), airway obstruction resulted in 17 surgical procedures before the age of 13 years. Sleep apnea was present in 8 of 10 individuals. In the nine unrelated individuals, ZBTB7A variants were novel and de novo. The six frameshift/nonsense and four missense variants were spread throughout the gene. This is the first report of a cohort of individuals with this novel syndromic neurodevelopmental disorder.

A novel lethal recognizable polymicrogyric syndrome caused by ATP1A2 homozygous truncating variants.

Polymicrogyria is a heterogeneous malformation of cortical development microscopically defined by an excessive folding of the cortical mantle resulting in small gyri with a fused surface. Polymicrogyria is responsible for a wide range of neurological symptoms (e.g. epilepsy, intellectual disability, motor dysfunction). Most cases have a supposed environmental clastic vascular or infectious origin but progress in genomics has revealed new monogenic entities. We report four cases from two independent families sharing a common recognizable lethal syndromic polymicrogyria of autosomal recessive inheritance. Beyond diffuse polymicrogyria detected prenatally, pathological examination revealed a common pattern associating meningeal arterial calcifications, necrotic and calcified areas in basal ganglia, dentato-olivary dysplasia and severe hypoplasia/agenesis of the pyramidal tracts. In all affected cases, exome sequencing showed a pathogenic homozygous nonsense ATP1A2 variant. This resulted in absence of immunodetectable ATP1A2 protein in two brains analysed. ATP1A2 encodes the alpha-2 isoform of the Na+/K+-ATPase, which is highly expressed in brain tissues and has previously been related to familial hemiplegic migraine (MIM#602481) and alternating hemiplegia of childhood (MIM#104290). Through the description of this genetic entity, we emphasize the possibility of dual mode of transmission for disease-causing genes and provide the key neuropathological features that should prompt geneticists to test for mutations in the ATP1A2 gene.