Glossary

Phenotype

All morphological and functional attributes of an individual or of the organs, tissues or cells of that individual, except for the primary morphology of the genome.

Cohesin complex

A multisubunit protein complex that mediates sister chromatid cohesion and cellular long-distance chromatin interactions. In vertebrates, the cohesin complex is composed of structural maintenance of chromosomes protein 1A (SMC1A), SMC3, RAD21 and cohesin subunit SA1 (also known as STAG1).

Genotype

The primary DNA sequence, either overall or at a specific locus, of an individual or of the organs, tissues or cells of that individual.

Rett syndrome

A severe, progressive neurological disorder primarily affecting females that is mainly caused by mutations in the gene encoding methyl-CpG-binding protein 2 (MECP2). It is characterized by loss of acquired speech and motor skills, repetitive hand movements, breathing irregularities and seizures.

Cohesinopathies

Disturbances of the function of the cohesin complex that lead to altered human development.

Delphi consensus process

A structured communication process between a panel of experts.

Mosaicism

The presence of two or more populations of cells with different genotypes in a single individual, who has developed from a single fertilized egg cell.

Facial gestalt

The unified pattern of elements of facial characteristics that cannot be derived from the simple summation of its elements.

Cell-free fetal DNA

Circulating DNA in maternal plasma originating from the fetus.

Multiplex ligation-dependent probe amplification

(MLPA). A molecular technique involving the ligation of two adjacent annealing oligonucleotides followed by quantitative PCR amplification of the ligated products, allowing the characterization of chromosomal aberrations in copy number or sequence and single nucleotide polymorphism or mutation detection.

Chalazion

Small swelling of the eyelid due to a blocked meibomian gland.

Strabismus

Strabismus (or squint or ‘crossed eyes’) is non-parallel orientation of the visual axes of the eyes causing a disturbed vision, which can be inwards (esotropia) or outwards (exotropia).