Ectodermal Dysplasia, Ectrodactyly, and Macular Dystrophy (EEM) Syndrome

At a glance

EEM is an acronym that stands for Ectodermal dysplasia, Ectrodactyly, and Macular dystrophy Syndrome. This genetic disorder affects ectoderm derivatives, upper and lower extremities, and retina. The clinical features include hypotrichosis with sparse and short hair on the scalp, sparse and short eyebrows and eyelashes, and partial anodontia. The hands are often more severely affected than the feet. The anomalies vary from the absence of digits to polydactyly, syndactyly, and camptodactyly. The retinal lesion appears as a central geographic atrophy of the retinal pigment epithelium and choriocapillary layer of the macular area with coarse hyperpigmentation and sparing of the larger choroidal vessels.

Synonyms

EEM-Albrectsen Syndrome; Albrectsen-Svendsen Syndrome; Ohdo-Hirayama-Terawaki Syndrome.

Incidence

Unknown, but approximately 13 cases from five families have been described to date in the literature.

Genetic inheritance

Autosomal recessive with parental consanguinity as a risk factor. Variable expression or genetic heterogenicity is suspected. This inheritance pattern is suggested in the presence of multiple affected individuals within the same family, especially when parents do not have the disease. It affects both sexes equally. A possible role for a third gene called CDH3 (responsible gene for the shape of the hand) has been recognized with ectrodactyly. The phenotypic differences between EEM and congenital hypotrichosis with juvenile macular dystrophy (HJMD) have been suggested considering that both are caused by CDH3 mutations. Ectrodactyly occurs as an isolated trait with at least five known loci and as part of many syndromes. Mutations in TP63 have been shown in isolated split hand-foot malformation.

Pathophysiology

Remains to be determined. Although, the discovery of a CDH3 mutations leads to an involvement of the cadherin that can cause limb malformations in humans. Classical cadherins are calcium-dependent adhesion molecules that are acting as dimers in homophilic binding.

Diagnosis

Based on family history, specific clinical features, radiologic studies, and ophthalmologic examination.

Clinical aspects

Ectodermal dysplasia may present with sparse and thin scalp hair, eyebrows and eyelashes, partial anodontia, and small, widely spaced teeth. Ectrodactyly of the upper and lower extremities can be associated with syndactyly and/or clefting of hand and feet. Hypoplastic distal phalanx of the index finger with onychodysplasia has been described. Ocular fundus examination reveals presumably progressive macular dystrophy and optic nerve changes. Sweating seems to be unaffected. Mild developmental delay may occur.

Precautions before anesthesia

There are no specific precautions to be taken prior to anesthesia with this medical condition. Most patients will be seen for ophthalmological procedures. As per routine, other medical considerations may require proper preoperative evaluation.

Anesthetic considerations

Peripheral intravenous access can be challenging because of ...