| Item | Value | Evidence/Source (include PMID if present) | URL | Notes |
|---|---|---|---|---|
| Definition | Rare congenital form of isolated/congenital hypogonadotropic hypogonadism characterized by impaired smell (anosmia or hyposmia) together with GnRH deficiency/HH | Laitinen et al., *Orphanet J Rare Dis* (2011): KS is “comprised of congenital hypogonadotropic hypogonadism (HH) and anosmia” (PMID not available in provided context); Żak 2024 review: “rare congenital disorder characterized by hypogonadotropic hypogonadism and anosmia or hyposmia” (pqac-00000003, pqac-00000007) | https://doi.org/10.1186/1750-1172-6-41 | Disease-level information derived from aggregated literature/research cohorts rather than individual EHR records |
| Minimal incidence in Finland (overall) | 1:48,000 | Laitinen et al., *Orphanet J Rare Dis* 2011, Finnish epidemiologic study; abstract reports “The minimal incidence estimate of KS in Finland was 1:48 000” (pqac-00000003) | https://doi.org/10.1186/1750-1172-6-41 | Population-based national estimate; often cited as a benchmark because true prevalence is difficult to ascertain |
| Minimal incidence in Finland (males) | 1:30,000 | Laitinen et al., *Orphanet J Rare Dis* 2011; abstract reports male incidence 1:30,000 (pqac-00000003) | https://doi.org/10.1186/1750-1172-6-41 | Consistent with later review summaries citing ~1:30,000 males |
| Minimal incidence in Finland (females) | 1:125,000 | Laitinen et al., *Orphanet J Rare Dis* 2011; abstract reports female incidence 1:125,000 (pqac-00000003) | https://doi.org/10.1186/1750-1172-6-41 | Female underdiagnosis is widely suspected because milder/less obvious pubertal findings may delay recognition |
| Sex ratio / sex bias | Marked male predominance; approximately 3–5-fold more frequent in males; Finland data imply ~4.2:1 male:female incidence ratio | Laitinen et al. 2011 notes KS is “3–5 times more frequent in men”; Żak 2024 review reports ~1:30,000 in males vs ~1:125,000 in females; Meczekalski et al. 2013 reports male:female ratio ~4:1 to 5:1 (pqac-00000003, pqac-00000007, pqac-00000004) | https://doi.org/10.1186/1750-1172-6-41; https://doi.org/10.3109/09513590.2012.752459 | Ratio varies across sources because of ascertainment differences and historical under-recognition in females |
| Prevalence/incidence estimates in reviews | Commonly cited estimates: ~1:30,000 males and ~1:125,000 females; older review also cites 1:10,000 males and 1:50,000 females | Żak 2024 review summarizes ~1:30,000 males and ~1:125,000 females; Meczekalski et al. 2013 gives older/higher estimates of 1:10,000 males and 1:50,000 females (pqac-00000007, pqac-00000004) | https://doi.org/10.3109/09513590.2012.752459 | Differences likely reflect methodology, diagnostic criteria, and evolving ascertainment, especially in women |
| Sporadic vs familial cases | ~60% sporadic | Laitinen et al. 2011 states that approximately 60% of KS cases are sporadic (pqac-00000003) | https://doi.org/10.1186/1750-1172-6-41 | Familial cases occur with X-linked, autosomal dominant, autosomal recessive, and oligogenic inheritance |
| Familial/genetic heterogeneity note | Multiple inheritance modes: X-linked recessive, autosomal dominant, autosomal recessive, and oligogenic inheritance | Laitinen et al. 2011 lists KAL1/ANOS1, FGFR1, FGF8, PROK2, PROKR2, CHD7, WDR11 and notes heterogeneous inheritance; Żak 2024 review similarly summarizes inheritance patterns (pqac-00000003, pqac-00000007) | https://doi.org/10.1186/1750-1172-6-41 | Important for counseling because recurrence risk depends on the causal gene and penetrance |
| Diagnostic timing context | Most cases are diagnosed in adolescence | Żak 2024 review notes most cases are recognized during adolescence when absent/incomplete puberty becomes evident (pqac-00000000) | N/A | Neonatal male signs such as micropenis/cryptorchidism may enable earlier detection in some patients |


*Table: This table summarizes core disease-definition and epidemiology facts for Kallmann syndrome, emphasizing the frequently cited Finnish incidence estimates and the marked male predominance. It also highlights the distinction between sporadic and familial disease, which is useful for knowledge-base curation and genetic counseling context.*