Mosaic disorders affecting pigmentation - part 2: how to make a genetic diagnosis.

Br J Dermatol

NHS England Rare Disease Collaborative Network for Mosaic Disorders, Paediatric Dermatology department, Great Ormond Street Hospital for Children, London, UK.

Published: July 2025


Category Ranking

98%

Total Visits

921

Avg Visit Duration

2 minutes

Citations

20

Article Abstract

Mosaic disorders affecting pigmentation are a large group of different rare diseases which present with hypo- and/or hyper-pigmented birthmarks. These can carry associated risks such as involvement of other organ systems, a predisposition to cancer, and the possibility of transmission to future offspring as germline disease. This review draws on the clinical and genetic discoveries of the last decade to discuss how to make a genetic diagnosis in mosaic disorders affecting pigmentation. Practicalities reviewed include how to take the right samples for testing and how to process the samples correctly, whilst key concepts include understanding variant allele frequency, variants of uncertain significance and sensitivity of genetic testing. It then goes on to demonstrate how to use the clinical classification established in part 1 of this two-part review to decide which genetic tests to perform and in which order. All currently known genetic causes of mosaic disorders affecting pigmentation are detailed, along with which variants have the potential for germline transmission to the next generation.

Download full-text PDF

Source
http://dx.doi.org/10.1093/bjd/ljaf224DOI Listing

Publication Analysis

Top Keywords

mosaic disorders
16
disorders pigmentation
16
genetic diagnosis
8
diagnosis mosaic
8
genetic
6
mosaic
4
pigmentation
4
pigmentation genetic
4
pigmentation large
4
large group
4

Similar Publications

Haemaphysalis leporispalustris (the rabbit tick) is one of the most broadly distributed hard tick species in the Americas. In 2018, investigators amplified DNA from a spotted fever group Rickettsia (SFGR) species found in host-seeking larvae and nymphs of H. leporispalustris collected in northern California and proposed the name Candidatus "Rickettsia lanei" using results obtained via multilocus sequence typing.

View Article and Find Full Text PDF

Background: Genetic modifiers are believed to play an important role in the onset and severity of polycystic kidney disease (PKD), but identifying these modifiers has been challenging due to the lack of effective methodologies.

Methods: We generated zebrafish mutants of IFT140, a skeletal ciliopathy gene and newly identified autosomal dominant PKD (ADPKD) gene, to examine skeletal development and kidney cyst formation in larval and juvenile mutants. Additionally, we utilized ift140 crispants, generated through efficient microhomology-mediated end joining (MMEJ)-based genome editing, to compare phenotypes with mutants and conduct a pilot genetic modifier screen.

View Article and Find Full Text PDF

Background: Turner syndrome (TS), also known as congenital ovarian hypoplasia, is one of the most common sex chromosome diseases in women. It is caused by the complete or partial deletion or structural change of one X chromosome in all or part of somatic cells. A rare case of karyotype Turner syndrome is reported.

View Article and Find Full Text PDF

Congenital heart disease (CHD) is the most common congenital anomaly. While surgical and interventional advancements have improved survival, the management of associated complications and comorbidities remains complex and would benefit from a personalised approach that more accurately predicts individualised risks and prognoses. Recently, next-generation sequencing has uncovered diverse genetic factors, including epigenetic modifications, somatic mosaicism and regulatory non-coding variants.

View Article and Find Full Text PDF

McCune-Albright syndrome (MAS) is a rare genetic disorder characterized by a triad of café-au-lait spots, fibrous dysplasia, and hyperfunctioning endocrinopathies, resulting from a mosaic mutation in the guanine nucleotide-binding protein (GNAS) gene. This case report presents the long-term follow-up of an eight-year-old girl diagnosed with MAS, who first presented at 22 months of age with skin pigmentation, hyperthyroidism, and precocious puberty, later developing additional features such as fibrous dysplasia and growth hormone excess. This complex presentation of MAS-featuring more than two hyperfunctioning endocrinopathies along with fibrous dysplasia-has rarely been described in the literature.

View Article and Find Full Text PDF