Defined by aplasia cutis congenita, asymmetric transverse limb defects, and cutis marmorata telangiectatica congenita. Heart defects and other anomalies of the internal organs must be ruled out.
Congenital Scalp Defects with Distal Limb Reduction Anomalies; Absence Defect of Limbs, Scalp, and Skull.
Described in 1945 by the two American physicians Forrest H. Adams and C.P. Oliver.
Based on the underlying mutations and mode of inheritance, six different types of AOS can be distinguished:
|Type ||Location ||Inheritance |
|Adams-Oliver Syndrome 1 ||3q13.32-q13.33 ||Autosomal dominant |
|Adams-Oliver Syndrome 2 ||19p13.2 ||Autosomal recessive |
|Adams-Oliver Syndrome 3 ||4p15.2 ||Autosomal dominant |
|Adams-Oliver Syndrome 4 ||3p14.1 ||Autosomal recessive |
|Adams-Oliver Syndrome 5 ||9q34.3 ||Autosomal dominant |
|Adams-Oliver Syndrome 6 ||15q15.1 ||Autosomal dominant |
The estimated incidence is approximately 1 in 225,00 live births. Both sexes are equally affected.
It is mainly autosomal dominant (in some families with reduced penetrance), but an autosomal recessive form has also been described, and some cases appear to be sporadic (new mutations). There is significant (even intrafamilial) variability in expression and penetrance with a wide spectrum of phenotypes ranging from minor skin and limb defects to lethal anomalies.
The pathophysiologic mechanism of AOS remains unknown. Common theories focus mainly around a vascular pathogenesis like congenital, developmental defect of small vessels, abnormal pericyte recruitment to vessels, or interruption of early embryonic blood supply to affected areas. However, other explanations such as neural tube closure defects, amniotic adhesions, or external compressions in utero have also been mentioned.
The diagnosis is primarily based on the clinical triad of aplasia cutis congenita (ACC, in about 80% of patients), transverse distal limb anomalies (in >80% of patients) and ☞Cutis Marmorata Telangiectatica Congenita (CMTC; in about 20% of patients).
Intrauterine growth retardation is a common finding. The congenital ACC defect is often solitary and typically (in over 90% of patients) affects the midline of the scalp on the vertex of the skull (or the parietal regions) and can be associated with underlying skull bone defects and dilated scalp veins converging to the skin defect. ACC lesions of more than 5 cm in diameter may require surgery with skin grafting and have a tendency to affect the skull bone and even the dura, resulting in a higher risk for potentially lethal complications, such as infections (fatal meningitis), thrombosis, hemorrhage (fatal or near fatal bleeding from the sagittal sinus), or cerebrospinal fluid (CSF) leak. Smaller defects are most often limited to the skin and usually heal with only minimal interventions over a period of months. ...