ESPE Abstracts

Objective: Monosomy 18q and 10p duplications rare chromosomal disorders that are caused by deletion of a part of the long arm (q) of chromosome 18 and duplication of genetic material on the short arm (P) of chromosome 10 respectively. In both disorders the phenotype is highly variable and; includes short stature, developmental delay, hypotonia, and facial dysmorphic features. Also, genital abnormalities could occur in both disorders. Genital abnormalities (cryptorchidism, micropenis, rarely hypospadias in boys; hypoplastic labia in girls) have been reported in 25-63% of individuals with monosomy 18q syndrome, and in nearly 50% of cases with 10p duplication. In most cases, there is more one segmental imbalances that accompanies each other due to inherited segregation of unbalanced translocations. Here, we present an undervirilized male case with 18q monosomy and 10p duplication.

Case: A five-month-old male patient was referred for hypospadias. He was born at 36 weeks of gestation with a birth weight of 2630 gr after an uneventful pregnancy to parents who were nonconsanguineous. He was followed in the neonatal intensive care unit due to suspicion of congenital adrenal hyperplasia and during follow-up, no hypoglycemia or electrolyte disorder was detected. He presented with a weight of 6.5 kg (-1.2SDS), a height of 63 cm (-1.24 SDS) and a head circumference of 39 cm (-3.02 SDS). There was an umbilical reductable hernia. The gonads (1/1 ml) were palpable in the labioscrotal folds the phallus was 2.5 cm in length and the cavernous tissue was thin. The urogenital sinus had one opening into the perineum. Gonadotropins and androgens that measured during the minipuberty (1 month old), ruled out the diagnosis of androgen synthesis defects and hypogonadism (FSH 3.7 mIU/Mll, LH 14.88 mIU/Ml, total testosterone 262 ng/dl, 1.4-Delta androstenedione 1.94 nmol/L). Due to microcephaly, VEP was performed and bilaterally prolonged p100 latency was detected; BAEP and cranial MRI was unremarkable. Chromosome analysis revealed 18q monosomy and 10p duplication (46,XY, der(18)t(18;10)(q21;p11.2)). In the segregation analysis, the father's chromosome analysis was 46,XY,t(10;18)(p11.2;q21) and he was a translocation carrier.

Conclusion: Chromosomal anomalies should be kept in mind in patients with multisystemic findings in addition to genital anomalies. This case has a very rare association of 18q partial monosomy and 10p duplication and is one of the segmental anomalies that can be diagnosed by chromosome analysis.

Keywords: micropenis, hypospadias, microcephaly, translocation, anosomy, monosomy