A CASE OF KLINEFELTER’S SYNDROME ASSOCIATED TO POLAND’S SYNDROME

The patient, a 17 years old man, who came to our attention for thinness, was 1.84 m tall and weighed 57 kg (BMI 16.83 kg/m2). He had a testicular volume of 4 ml and increased consistency bilaterally and was normally androgenized. The semen analysis showed normal seminal fluid volume and azoospermia. Blood lymphocyte chromosomal evaluation showed a classical KS karyotype (47,XXY). In addition, at the physical examination, he had a marked atrophy of the pectoral and mammary muscles especially in the right side, associated with pectumexcavatum. Computed tomography showed hypoplasia of the right pectoralis major muscle, with reduced subcutaneous fat on the ipsilateral side of the chest, with abnormalities of the ribs on the same side but absent upper limb deformities. Genetic counseling confirmed the presence of a rare syndrome characterized by underdeveloped chest muscles and mammary gland called Poland syndrome (PS). PS is a rare disorder (1/30,000-32,000 births with a higher prevalence in males: 2:1-3:1) characterized by hypoplasia/aplasia of the pectoralis major muscle, variably associated with thoracic and upper limb anomalies. It comprises a spectrum of chest-wall deformities affecting, to various degrees, the rib cage, the chest-wall muscles, neurovascular structures of the ipsilateral arm and the overlying breast. Familial recurrence with higher prevalence in males has been reported indicating that PS could have a genetic basis, though the genetic mechanisms underlying PS development are still unknown. No other family members of the propositus resulted to be affected by PS. Different inheritance patterns (autosomal recessive or dominant, and dominant with incomplete penetrance) have been reported. A development impairment suggests an abnormal function of genes regulating cell proliferation and/or differentiation. Accordingly, it has been recently proposed that all forelimb elements (skeletal structures, proximal and distal muscles and sternum) develop according to a unique program. Deletion at chromosome 11q12.3 has been described.PS may result from a vascular insult during early embryo development, thusenvironmental factors may contribute to its onset. To our knowledge this is the first report showing an association between KS and PS. We hypothesize that the endothelial damage already described in patients with KS may increase, in genetically predisposed subjects, the vascular defect which cause PS.