Program Nr: 600 for the 2006 ASHG Annual Meeting

Penoscrotal transposition and other anomalies in patients with distal 13q deletion syndrome. J.R. Corona-Rivera1,2, J. Acosta-León2, V.A. Gutiérrez-García1, E. López-Marure2, A. Corona-Rivera1, L. Bobadilla-Morales1. 1) Instituto de Genética Humana, CUCS, Universidad de Guadalajara, Guadalajara, México; 2) División de Pediatría, Hospital Civil de Guadalajara "Dr. Juan I. Menchaca", Guadalajara, México.
   Complete or partial penoscrotal transposition (PST) is a rare abnormality, frequently associated with other malformations involving the genitourinary, cardiovascular or skeletal systems. Deletions of different portions of chromosome 13 are related with variable features of 13q deletion syndrome as well as with complete or partial PST. We report a patient with del(13)(q32) and partial PST and review the 13q breakpoints previously related to PST. The propositus was born to 20-years-old G2, P2 mother and 37-years-old healthy non-consanguineous father. He was born at term after uncomplicated pregnancy and delivery. Birth weight was 1,800 g and length 44 cm (both below 3rd centile). He presented delayed development of motor skills. Physical examination showed weight 2200 g (-4.7 SD), height 47.5 cm (-3.4 SD), OFC 31.2 cm (-4.8 SD). He had a 1.3 cm cystic mass just below the posterior fontanelle, broad nasal bridge, upward obliquity of the palpebral fissures, small receding chin, short neck, hearth murmur, single palmar crease on both hands, extra digital creases on some digits and hiperconvex nails. He also had partial PST with bifid but well developed scrotum and testis, hypospadias and a perineal sinus. Ultrasonographic evaluation of cranial cystic mass suggested a dermoid cyst. An echocardiogram showed patent foramen ovale. Cystography and abdominal ultrasound did not show other renal or genitourinary anomalies. Cranial CT scan showed mild atrophy. Karyotype was 46,XY,del(13)(q32). The overall phenotype in our patient was strikingly similar to those previously reported in patients with different deletion of chromosome regions located betweeen 13q22-13q34. Since some previous reports of PST had a similar pattern of defects of the facial, genital, cardiovascular and limb regions, but with apparent normal karyotype, we speculate that cryptic deletions of the PST critical region may be related to this cases.