Cutis Laxa

At a glance

Cutis laxa refers to a connective tissue disorder characterized by the lack of skin elasticity and manifesting mostly by hanging or wrinkled skin. Clinically, the affected skin is thickened and dark.

Synonyms

Generalized Chalazodermia; Generalized Dermatochalasia; Generalized Elastorrhexis; Generalized Elastolysis Syndrome; Urban-Rifkin-Davis Syndrome; Occipital Horn Syndrome (formerly known as X-linked Cutis Laxa or Ehlers-Danlos Syndrome Type IX); Arterial Tortuosity Syndrome; RIN2 Syndrome (Macrocephaly, Alopecia, Cutis Laxa, Scoliosis Syndrome; MACS).

Incidence

Cutis laxa (CL) is a rare skin disorder that affects males and females in equal numbers. Approximately 200 families have been reported in the medical literature. Most cases of CL are inherited as an autosomal recessive trait.

Genetic inheritance

CL is either acquired or inherited. Inheritance can be autosomal dominant, autosomal recessive, or X-linked. The autosomal recessive form is not only the most frequent, but also the most severe type. Here, we will focus on the inherited variants. Several mutations can cause CL. Autosomal recessive CL can be caused by mutations in nine different genes, with the most common ones being the ATP6V0A2 (Lysosomal H⁺ Transporting ATPase, V0 Subunit A2) gene on chromosome 12q24.31, ATP6V1A (Lysosomal H⁺ Transporting ATPase, V1 Subunit A) gene on chromosome 3q13.31, EFEMP2 (EGF-Containing Fibulin-Like Extracellular Matrix Protein 2, also known as FBLN4, Fibulin 4) gene on chromosome 11q13.1, FBLN5 (Fibulin 5) gene on chromosome 14q32.12, or LTBP4 (Latent Transforming Growth Factor-Beta-Binding Protein 4) gene on chromosome 19q13.2. The autosomal dominant variants can be caused by mutations in the ELN (Elastin) gene located on chromosome 7q11.23, FBLN5 (Fibulin 5) gene on chromosome 14q32.12 (similar to the autosomal recessive form), or the ALDH18A1 (Aldehyde Dehydrogenase 18 Family, Member A1) on chromosome 10q24.1. Most of these genes are involved in the biosynthesis, secretion, transport, activation, or polymerization of elastin. The disorder formerly known as X-linked CL has been renamed Occipital Horn Syndrome, is caused by mutations in the ATP7A (Cu²⁺-Transporting ATPase, Alpha Polypeptide) gene on chromosome Xq21.1. The acquired forms of CL may develop following a severe illness (eg, malignancies) involving fever, polyserositis, or erythema multiforme. It is thought that acquired CL results from autoimmune processes.

Pathophysiology

The main structural skin anomalies in CL are a lack, fragmentation, and/or disorganization of elastic fibers that, depending on the genetic defect, can involve other tissues. Elastin is synthesized in fibroblasts and smooth muscle cells and secreted as tropoelastin, the precursor of elastin. The elastic complex in the dermis is composed of elastic, elaunin, and oxytalan fibers. The main bulk of elastin is produced during fetal life with minimal turnover after birth.