Table 3.

Special features of Klinefelter variants

Karyotype	Age at diagnosis (months)	Behavioral issues	Intelligence	Comorbidities
49 XXXXY	12	Yes	Subnormal	ASD with PAH
48 XXYY	12	Yes	MR	VACTERL anomaly
48 XXYY	24	NA	Subnormal	Global developmental delay Dysmorphism
49 XXXXY	18	Yes	Low	VSD Dysmorphism
47 XXY/48 XXXY/49 XXXXY	15	Yes	Subnormal	Hypothyroidism Dysmorphism
49 XXXXY/48 XXXY/46 XX	84	Yes	MR	ASD Dysmorphism Proximal Radio-Ulnar Synostosis

MR=Mental Retardation; NA=Not Available; VACTERL=Vertebral defects, Anal atresia, Cardiac defects, Tracheo-Esophageal fistula, Renal anomalies, Limb abnormalities; VSD=Ventricular Septal Defect; ASD=Atrial Septal Defect