Osteopetrosis is a collective term for a range of sclerosing bone diseases resulting from an absence or defective function of osteoclasts. The clinical expression is variable and includes skeletal, hematological and neurological manifestations. The common neurological manifestation includes cranial neuropathies involving optic, cochlear, facial and trigeminal nerves. Spastic quadriplegia occurring as a result of brain stem compression in osteopetrosis is uncommon. The association of Type 1 Arnold Chiari malformation with osteopetrosis resulting in brain stem compression syndrome is an extremely rare entity.

Kallmann's syndrome is a rare genetic disorder due to abnormal migration of olfactory axons and gonadotropin releasing hormone producing neurons, characterized by hypogonadism and anosmia. The prevalence of Kallmann's syndrome is 1:10,000 to 1:60,000 with a male to female ratio of 5:1. The inheritance of Kallmann's syndrome may be X-linked, autosomal recessive or autosomal dominant with variable penetrance, mutation involving KAL-1 and KAL-2 gene respectively. We report a case of Kallmann's syndrome in a 19-year-old boy with characteristic clinical, biochemical and MRI findings.