Unexpected High Prevalence of Focal Facial Dermal Dysplasia (FFDD) Type IV Is Linked to a Founder Effect in the Belgian Population.

Focal facial dermal dysplasia (FFDD) type IV is a rare inherited facial defect caused by biallelic variants in CYP26C1. This study reports two novel Belgian FFDD type IV cases, both homozygous for a recurrent CYP26C1 frameshift variant, with a common 700 kb haplotype, indicating a founder effect.

A heatmap for expected cumulative live birth rate in preimplantation genetic testing for monogenic disorders and chromosomal structural rearrangements.

Purpose: Our objective is to predict the cumulative live birth rate (CLBR) and identify the specific subset within the population undergoing preimplantation genetic testing for monogenic disorders (PGT-M) and chromosomal structural rearrangements (PGT-SR) which is likely to exhibit a diminished expected CLBR based on various patient demographics.

Methods: We performed a single-centre retrospective cohort study including 1522 women undergoing 3130 PGT cycles at a referral centre for PGT. A logistic regression analysis was performed to predict the CLBR per ovarian stimulation in women undergoing PGT-M by polymerase chain reaction (PCR) or single-nucleotide polymorphism (SNP) array, and in women undergoing PGT-SR by SNP array, array comparative genomic hybridization (CGH) or next-generation sequencing (NGS).

Pathogenic variants in HGF give rise to childhood-to-late onset primary lymphoedema by loss of function.

Developmental and functional defects in the lymphatic system are responsible for primary lymphoedema (PL). PL is a chronic debilitating disease caused by increased accumulation of interstitial fluid, predisposing to inflammation, infections and fibrosis. There is no cure, only symptomatic treatment is available.

Prenatal phenotype of a homozygous nonsense MPDZ variant in a fetus with severe congenital hydrocephalus.

The fetal phenotype of MPDZ-associated congenital hydrocephalus type 2 with or without brain or eye anomalies (HYC2) (OMIM 615219) is not well described in the literature. The present case shows not previously published clinical fetal features that are detected during routine second trimester ultrasound screening at 21 weeks of gestation such as bilateral ventriculomegaly, lean cavum septum pellucidum, suspicion of hypoplastic corpus callosum, and suspicion of gyration disorder with normal fossa posterior. Combination of clinical features and a gene panel for congenital malformation syndromes detected a homozygous, likely pathogenic nonsense variant in the MPDZ gene.