| Phenotype | HPO term(s) | Frequency (Campeau 2012) | Frequency (Yabumoto 2021 GPS) | Notes |
|---|---|---|---|---|
| Patellar aplasia/hypoplasia | HP:0006498 Absent patella; HP:0006388 Hypoplastic patella | 18/19 absent or hypoplastic patellae | 6/6 abnormal patella | Cardinal skeletal feature of GPS; often absent or severely hypoplastic rather than mildly small (pqac-00000016, pqac-00000030) |
| Flexion contractures / contractures | HP:0001371 Flexion contracture; HP:0002804 Hip flexion contracture; HP:0005047 Knee flexion contracture | 19/19 flexion deformities | 6/6 contractures | Major diagnostic feature; often involves hips and knees and may contribute to impaired mobility (pqac-00000016, pqac-00000030) |
| Clubfoot | HP:0001762 Talipes equinovarus | ~18/19 | Not separately quantified in extracted GPS subset | Often grouped with lower-limb contractures in GPS descriptions (pqac-00000016, pqac-00000023) |
| Microcephaly | HP:0000252 Microcephaly | 19/19 | 7/7 | Highly consistent neurodevelopmental feature across cohorts (pqac-00000016, pqac-00000030) |
| Corpus callosum abnormality | HP:0001274 Agenesis of corpus callosum; HP:0002079 Hypoplasia of corpus callosum | 15/19 absent or thin corpus callosum | Not explicitly tabulated in extracted GPS subset | Core CNS malformation in GPS and a key differential feature versus some milder KAT6B phenotypes (pqac-00000016, pqac-00000023) |
| Developmental delay / intellectual disability | HP:0001263 Global developmental delay; HP:0001249 Intellectual disability | 16/16 developmental delay/intellectual disability | 7/7 developmental delay/intellectual disability | Universal or near-universal; severe psychomotor impairment is characteristic of classic GPS (pqac-00000016, pqac-00000030) |
| Severe language impairment | HP:0001344 Severe global developmental delay; HP:0000750 Delayed speech and language development | Not separately quantified | 7/7 profound/severe language impairment | Prominent functional/QoL impact; extracted as a distinct frequency only in the GPS subset table (pqac-00000030) |
| Delayed mobility / non-ambulatory status | HP:0001270 Motor delay; HP:0002505 Poor head control; HP:0002540 Delayed ability to walk | Not separately quantified | 7/7 delayed mobility/non-ambulatory | Reflects major functional burden from neurologic and orthopedic disease (pqac-00000030) |
| Hypotonia | HP:0001252 Hypotonia | Reported, but not quantified in extracted Campeau frequencies | 7/7 | Common across KAT6B-related disorders; contributes to feeding and motor delay (pqac-00000024, pqac-00000030) |
| Hydronephrosis | HP:0000126 Hydronephrosis | 11/16 or 11/19 reported in extracted table summary | 7/7 | Renal/urinary tract involvement is a classic GPS feature; denominator uncertainty reflects extracted summary wording from Table 1 (pqac-00000016, pqac-00000022, pqac-00000030) |
| Multicystic kidneys / renal cysts | HP:0000107 Renal cyst; HP:0000003 Multicystic kidney dysplasia | 6/19 multicystic kidneys | Not separately quantified | Supports frequent congenital renal involvement, though not universal (pqac-00000022, pqac-00000024) |
| Congenital heart defect (overall) | HP:0001627 Abnormal heart morphology; HP:0001631 Atrial septal defect; HP:0001629 Ventricular septal defect | ASD 7/19; VSD 4/19 | 6/7 ASD/VSD | Cardiac screening is important because septal defects are common in both cohorts (pqac-00000022, pqac-00000030) |
| Genital anomalies (overall) | HP:0000078 Abnormality of the genital system | Reported as defining feature, but not frequency-extracted from Campeau table here | Not frequency-tabulated in Yabumoto GPS subset table excerpt | Larger review found genital anomalies in 94% of GPS, supporting this as a hallmark feature (pqac-00000027) |
| Prenatal imaging abnormalities | HP:0000112 Abnormality of the genitourinary system; HP:0012443 Abnormal prenatal development or birth finding | Not available | 6/6 prenatal anatomy scan findings | Suggests many GPS cases are detectable prenatally by structural anomalies, though the specific anomalies vary (pqac-00000030, pqac-00000026) |
| Low-set / dysplastic ears | HP:0000369 Low-set ears; HP:0000377 Abnormal pinna morphology | Facial dysmorphism frequent (19/19 overall facial dysmorphism) | 6/6 low-set/posteriorly rotated/dysplastic ears | Facial findings are common but vary in specific expression across reports (pqac-00000016, pqac-00000030) |
| Bulbous nose | HP:0000414 Bulbous nose | Included within facial dysmorphism, not individually quantified | 6/6 | Helpful craniofacial clue, though not specific to GPS (pqac-00000016, pqac-00000030) |
| Long thumbs / great toes | HP:0011304 Broad thumb?; HP:0001177 Abnormal thumb morphology; HP:0001831 Broad hallux / abnormal great toe morphology | Not extracted as a Campeau GPS frequency | 5/6 | More classically emphasized in SBBYSS, but can also occur in GPS-spectrum patients (pqac-00000030, pqac-00000004) |
| Ptosis | HP:0000508 Ptosis | Facial dysmorphism frequent, but not individually quantified | 4/5 | Less specific for GPS than for SBBYSS, but still observed in some GPS cases (pqac-00000030, pqac-00000004) |
| Feeding difficulties | HP:0011968 Feeding difficulties | Reported clinically, not frequency-extracted from Campeau table here | 7/7 | Strong contributor to neonatal/infant morbidity and multidisciplinary care needs (pqac-00000022, pqac-00000030) |


*Table: This table summarizes key Genitopatellar syndrome clinical features with suggested HPO mappings and compares frequencies reported in the original Campeau 2012 cohort versus the GPS subset in Yabumoto 2021. It is useful for structured phenotype curation and for identifying high-consistency hallmark findings.*