Limb-Mammary Syndrome
Limb-mammary syndrome (LMS) is a rare disease belonging to the group of ectodermal dysplasias.
Epidemiology
Less than 50 cases have been described in the literature so far.
Clinical description
Clinically, the syndrome is characterized by severe hand and/or foot anomalies, and hypoplasia/aplasia of the mammary gland and nipple. Clinical expression is extremely variable. Individuals with mild LMS have isolated athelia. All three major categories of limb defects (i.e., deficiencies, duplications, and fusion/separation defects), as well as several combinations of these anomalies, were observed. Variation in the severity of the limb defects may be observed, not only between individuals but also between the left and right hand/foot of one individual. Less frequent findings include lacrimal-duct atresia, nail dysplasia, hypohydrosis, hypodontia (absence of one or more teeth), earpits and cleft palate with or without bifid uvula. Skin and hair are spared.
Etiology
LMS is caused by loss-of-function mutations in exon 13 and 14 of the TP63 gene localized to the subtelomeric region of chromosome 3 (3q27). There is a strong genotype-phenotype correlation in syndromes caused by mutations in this gene, which is also responsible for several other ectodermal dysplasia syndromes (ectrodactyly-ectodermal dysplasia-cleft lip palate (EEC), and the Hay-Wells, Rapp-Hodgkin and ADULT syndromes) and some cases of split hand-foot syndrome.
Differential diagnosis
Differential diagnosis should include ulnar-mammary syndrome, an autosomal dominant condition caused by mutations in the TBX3 gene and characterised by ulnar ray defects or post-axial polydactyly, anal atresia, genito-urinary abnormalities, hypohidrosis and breast hypoplasia.
Genetic counseling
LMS is an autosomal dominant disease.
Management and treatment
Treatment of LMS depends on the anomalies present. Surgical intervention may be offered for correction of the hand/foot deformities in order to improve function and reduce physical disfigurement.
Prognosis
The prognosis for LMS patients is good and life expectancy is normal.