Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen (e.g., estradiol) as hypoestrogenism. [Source: Wikipedia ]

Gonadal hypoplasia
Hypoplastic genitalia
May Cause
Delayed bone age
Enlargement or erosion of sella turcica
Generalized osteopenia or osteolysis of the jaws
Generalized osteoporosis
Large sella turcica
Spinal osteopenia
May Be Caused by
Achondrogenesis type 1
Alström syndrome
Androgen insensitivity syndrome
Ataxia - hypogonadism - choroidal dystrophy
Bardet-Biedl syndrome
Biemond syndrome type 2
Bloom syndrome
Börjeson-Forssman-Lehmann syndrome
Boucher-Neuhäuser syndrome
Brachmann-de Lange syndrome
Carpenter syndrome
Cataract - deafness - hypogonadism
Cataract - intellectual deficit - hypogonadism
Cerebellar ataxia - hypogonadism
Cockayne syndrome
Congenital muscular dystrophy - infantile cataract - hypogonadism
Cushing syndrome
De Sanctis-Cacchione syndrome
Ectodermal dysplasia
Fibrodysplasia ossificans congenita
Fröhlich syndrome
Goltz syndrome
Gorlin syndrome
Hallermann-Streiff syndrome
Harrod syndrome
Hydrocephalus - obesity - hypogonadism
Hypogonadism - mitral valve prolapse - intellectual deficit
IMAGe syndrome
Intellectual deficit - dysmorphism - hypogonadism - diabetes mellitus
Jaffe-Campanacci syndrome
Johnson-McMillin syndrome
Juberg-Marsidi syndrome
Kallmann syndrome
Klinefelter syndrome
Langerhans cell histiocytosis
Laron syndrome
Laurence-Moon syndrome
LEOPARD syndrome
Lin-Gettig syndrome
Marfan syndrome
Marinesco-Sjögren syndrome
Martsolf syndrome
Mauriac syndrome
MCA syndrome
MICRO syndrome
Mixed gonadal dysgenesis
Myotonic dystrophy
Najjar syndrome
Odontotrichomelic dysplasia
PAGOD syndrome
Polymicrogyria - turricephaly - hypogenitalism
Prader-Willi syndrome
Prasad syndrome
Prominent glabella - microcephaly - hypogenitalism
Reifenstein syndrome
Retinitis pigmentosa - intellectual deficit - deafness - hypogenitalism
Robinow syndrome
Rothmund-Thomson syndrome
Seckel syndrome
Summitt syndrome
Trisomy 21
Turner syndrome
Werner syndrome
Wiedemann syndrome
X-linked deafness and hypogonadism
X-linked intellectual deficit - hypogonadism - ichthyosis - obesity - short stature
XXXXY syndrome