Background: Micro-deletions of the long arm of the Y chromosome are associated with spermatogenic failure and infertility. In addition, it has been suggested that the Y long arm contains genes that control height. Among structural rearrangements, the isochromosome of Yp i(Yp) appears to be the most uncommon. In the literature no data regarding the course of puberty in boys affected by i(Yp) is described. Case Report: We describe a 13 years old boy with monolateral gynaecomastia who was referred to our Center. His auxological parameters were: height 151.4 cm (M SDS), weight 65.8 kg (+3 SDS) and bone age of 14 years. Genital development was stage 1. Baseline luteinizing hormone (LH) and follicle stimulating hormone (FSH) values were in the prepubertal range and testosterone (T) response to HCG stimulation test showed modest rise. Caryotype was 46 X i(Yp) with the FISH analysis confirming the presence of double SRY. No mutations in KAL1 gene was found. The pituitary MRI scan was normal with no abnormalities of olfactory system. At 15 years his parameters were: height of 158 cm (-1.8 SDS) weight of 63 Kg (+ 0,8 SDS) and a bone age of 16 years. His final height (FH) was – 2,8 SDS to Target Height (TH) (177 cm; +1 SDS) . Genital prepubertal development. Basal and stimulated levels of LH, FSH and T were prepubertal. Baseline inhibin B value was 44 pg/mL. Secondary sex characteristics were attained by exogenous testosterone enanthate (TE)replacement. Conclusion: We described the course of puberty in an adolescent with i(Yp), a rare genetic abnormality associated with male infertility. Our patient showed gynaecomastia, HH and short stature. Usually, male hypogonadism presenting during the period of bone growth will result in increased body height caused by retardation of androgen-induced closure of epiphyses. Our case support the existence of a Y-linked growth gene because the FH was significantly smaller than TH. Our case report of pertinent HH in a patient with i(Yp) may contribute to our understanding of patho-physiology of hypothalamic-pituitary-gonadal axis.
Isochromosome Yp in a boy with Hypogonadotropic Hypogonadism, Gynaecomastia and short stature
MAINES, Evelina;CAVARZERE, Paolo;MONTI, Elena;BANZATO, Claudia;LAURIOLA, Silvana;Doro, Francesco;Morandi, Grazia;ANTONIAZZI, Franco;GAUDINO, Rossella
2011-01-01
Abstract
Background: Micro-deletions of the long arm of the Y chromosome are associated with spermatogenic failure and infertility. In addition, it has been suggested that the Y long arm contains genes that control height. Among structural rearrangements, the isochromosome of Yp i(Yp) appears to be the most uncommon. In the literature no data regarding the course of puberty in boys affected by i(Yp) is described. Case Report: We describe a 13 years old boy with monolateral gynaecomastia who was referred to our Center. His auxological parameters were: height 151.4 cm (M SDS), weight 65.8 kg (+3 SDS) and bone age of 14 years. Genital development was stage 1. Baseline luteinizing hormone (LH) and follicle stimulating hormone (FSH) values were in the prepubertal range and testosterone (T) response to HCG stimulation test showed modest rise. Caryotype was 46 X i(Yp) with the FISH analysis confirming the presence of double SRY. No mutations in KAL1 gene was found. The pituitary MRI scan was normal with no abnormalities of olfactory system. At 15 years his parameters were: height of 158 cm (-1.8 SDS) weight of 63 Kg (+ 0,8 SDS) and a bone age of 16 years. His final height (FH) was – 2,8 SDS to Target Height (TH) (177 cm; +1 SDS) . Genital prepubertal development. Basal and stimulated levels of LH, FSH and T were prepubertal. Baseline inhibin B value was 44 pg/mL. Secondary sex characteristics were attained by exogenous testosterone enanthate (TE)replacement. Conclusion: We described the course of puberty in an adolescent with i(Yp), a rare genetic abnormality associated with male infertility. Our patient showed gynaecomastia, HH and short stature. Usually, male hypogonadism presenting during the period of bone growth will result in increased body height caused by retardation of androgen-induced closure of epiphyses. Our case support the existence of a Y-linked growth gene because the FH was significantly smaller than TH. Our case report of pertinent HH in a patient with i(Yp) may contribute to our understanding of patho-physiology of hypothalamic-pituitary-gonadal axis.
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