Page 103 - The Netter Collection of Medical Illustrations - Integumentary System_ Volume 4 ( PDFDrive )

Plate 4-18 Rashes

CUTIS LAXA

Cutis laxa is an unusual skin disease with multisystem
complications. It has highly characteristic cutaneous
findings. Laxity of the skin is the hallmark of this
disease. The skin becomes easily stretched, and there is
little elastic rebound. As patients age, gravity alone can
make the skin droop to a disfiguring degree. Some
forms of cutis laxa are incompatible with life, and those Cutis laxa. This rare disease is caused by the
affected die in infancy. Many variants of cutis laxa have premature degeneration of elastic fibers. It
been described. With the discovery of the responsible manifests clinically with excessive sagging
gene defects, the phenotypes of this disease that are of the skin. The affected face may take on a
seen clinically have been better defined on the genetic “hound dog” appearance.
level. Acquired variants of cutis laxa have been described.
Clinical Findings: Cutis laxa has no sexual or racial
predilection. The cutaneous hallmark of the disease is
loose, hanging skin with a lack of elasticity. The skin
can be pulled with little resistance; the normal return
of the skin to its preexisting state is delayed. The skin
in the axillae and groin folds is prominently affected, as
is the facial skin. The face is said to take on a “hound
dog” appearance. All skin is involved to varying degrees,
but the effects are most noticeable in areas of the face
and in the skin folds. The overlying epidermis is com-
pletely normal, and the adnexal structures are spared.
Internal manifestations are variable and are more
common with the autosomal recessive forms of the
disease. The pulmonary, cardiovascular, and gastroin-
testinal systems can be affected by fragmentation or loss
of elastic tissue, leading, respectively, to emphysema,
aneurysms, and diverticula.
Those with the autosomal dominant form appear to
have normal life spans, whereas those with the other
variants have significantly shortened life spans second-
ary to severe systemic involvement.
Pathogenesis: Many modes of inheritance have been
reported for cutis laxa, including autosomal recessive,
autosomal dominant, and X-linked recessive forms.
The X-linked form is now considered to be the same Cutis laxa is an inherited or acquired
disease as Ehlers-Danlos syndrome IX. This form is abnormality of elastic tissue. The skin
caused by a defect in a copper-dependent adenosine becomes loose over time and hangs
triphosphatase (ATPase) protein found within the from the body. Large folds of redundant
Golgi apparatus. skin present on the trunk.
There are two autosomal recessive variants of cutis
laxa. The autosomal recessive variant type I is extremely
rare, and those afflicted typically die early in infancy
from severe pulmonary and multisystem failure. Auto-
somal recessive type I cutis laxa has been found to be
caused by a defect in the fibulin-5 gene (FBLN5). The
product of this gene is critical in producing functional
elastic fibers. Its absence is incompatible with life. Type
II autosomal recessive cutis laxa is more commonly
encountered than type I. The genetic defect in type II
cutis laxa has yet to be defined. Patients with type II
experience developmental delay and have varying
amounts of joint laxity.
The most frequently seen form of cutis laxa is the
autosomal dominant form, which is caused by a defect
in the elastin gene (ELN). Many different mutations in
this gene have been described, and they lead to slightly Histology: Histological examination of skin biopsies Treatment: The main goals of therapy is to screen
different phenotypes of the disease. from patients with cutis laxa reveals varying degrees of for underlying cardiac or gastrointestinal abnormalities
All of these gene defects lead to abnormalities in the elastic fiber damage and /or loss. The best way to appre- and for the possibility of aortic aneurysm or gastroin-
elastic fiber protein, resulting in elastolysis. Various ciate this is with special staining to highlight elastic testinal diverticula formation. There is no medication
defects lead to different irregularities in the elastic tissue. In some cases, there is a complete loss of elastic that can reverse the genetic defect, and no gene replace-
fibers, but the end result in all forms is seen clinically fibers; in others, fragmented and reduced amounts of ment therapy is available. Excessive skin can be surgi-
as cutis laxa. elastic tissue are seen. cally removed to improve functionality and cosmesis.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 89