| Inbound Relationships | Type | Active | Source | Characteristic | Refinability | Group | 
| Birth head circumference | Is a | True | Head circumference | Inferred relationship | Some |  | 
| Head circumference centile | Is a | False | Head circumference | Inferred relationship | Some |  | 
| Fetal microcephaly (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Sporadic fetal brain disruption sequence | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Macrocephaly (finding) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Congenital macrocephaly (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Bannayan syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Facial dysmorphism, macrocephaly, myopia, Dandy-Walker malformation syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 8 | 
| Intellectual disability, seizures, macrocephaly, obesity syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 6 | 
| Macrocephaly and developmental delay syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Macrocephaly with spastic paraplegia and dysmorphism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 5 | 
| Macrocephaly, short stature, paraplegia syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Macrocephaly, obesity, mental disability, ocular abnormality syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Macrocephaly, intellectual disability, autism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Malan overgrowth syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Pectus excavatum, macrocephaly, dysplastic nails syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 6 | 
| Overgrowth, macrocephaly, facial dysmorphism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Heide syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Relative macrocephaly | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| X-linked intellectual disability Atkin type (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| X-linked recessive intellectual disability and macrocephaly with ciliary dysfunction syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| X-linked intellectual disability, macrocephaly, macroorchidism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Microcephaly (finding) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Secondary microcephaly | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Deficiency of leukotriene C4 synthase (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Infantile cerebral and cerebellar atrophy with postnatal progressive microcephaly | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Microcephaly, short stature, intellectual disability, facial dysmorphism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Microcephaly, thin corpus callosum, intellectual disability syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Severe neonatal onset encephalopathy with microcephaly (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Head circumference for age z-score (observable entity) | Is a | True | Head circumference | Inferred relationship | Some |  | 
| Early-onset progressive encephalopathy, hearing loss, pons hypoplasia, brain atrophy syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Microcephaly, congenital cataract, psoriasiform dermatitis syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Lethal hydranencephaly, diaphragmatic hernia syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 5 | 
| Severe intellectual disability, progressive postnatal microcephaly, midline stereotypic hand movements syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Progressive microcephaly, seizures, cortical blindness, developmental delay syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Child head circumference centile | Is a | True | Head circumference | Inferred relationship | Some |  | 
| Christianson syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Postnatal microcephaly, infantile hypotonia, spastic diplegia, dysarthria, intellectual disability syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Intrauterine growth restriction, congenital multiple café au lait macules, increased sister chromatid exchange syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Severe neurodevelopmental disorder with feeding difficulties, stereotypic hand movement, bilateral cataract | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Seizures, scoliosis, macrocephaly syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 2 | 
| Macrocephaly, intellectual disability, neurodevelopmental disorder, small thorax syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Macrocephaly, intellectual disability, left ventricular non compaction syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Congenital ichthyosis, microcephalus, tetraplegia syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Sanjad Sakati syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Progressive cerebello-cerebral atrophy (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Agenesis of corpus callosum, macrocephaly, hypertelorism syndrome (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 6 | 
| ITPA-related lethal infantile neurological disorder with cataract and cardiac involvement | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Phospholipase A2 activating protein-associated neurodevelopmental disorder (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 1 | 
| Global developmental delay, alopecia, macrocephaly, facial dysmorphism, structural brain anomalies syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Lethal fetal cerebrorenogenitourinary agenesis/hypoplasia syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Spastic tetraplegia, thin corpus callosum, progressive postnatal microcephaly syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| PYCR2-related microcephaly, progressive leucoencephalopathy | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Fatty acyl-coenzyme A reductase 1 deficiency (disorder) | Interprets | True | Head circumference | Inferred relationship | Some | 6 | 
| USP18 deficiency | Interprets | True | Head circumference | Inferred relationship | Some | 3 | 
| Intellectual disability, macrocephaly, hypotonia, behavioural abnormalities syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 7 | 
| Menke Hennekam syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 4 | 
| Megalencephaly, severe kyphoscoliosis, overgrowth syndrome | Interprets | True | Head circumference | Inferred relationship | Some | 5 | 
| Head circumference of fetus | Is a | True | Head circumference | Inferred relationship | Some |  |