Klinefelter syndrome: expanding the phenotype and identifying new research directions.
OBJECTIVE
The purpose of this study is to summarize new data on etiology and clinical features of Klinefelter syndrome in order to derive research priorities.


METHODS
This study was conducted using critical reviews of selective topics, emphasizing less well-recognized clinical findings.


CONCLUSIONS
The phenotype of the prototypic 47,XXY case is well recognized: seminiferous tubule dysgenesis and androgen deficiency. Less well appreciated is the varied expressivity of 47,XXY Klinefelter syndrome, in particular neurological/cognitive perturbations like language and behavioral problems. Effective therapies are available. Reproductive technologies allow 47,XXY men to sire offspring through intracytoplasmic sperm injection (ICSI); however, genetic counseling is complex and success is low. Behavioral and expressive language difficulties are amenable to treatment by androgen therapy and psychological help. Early treatment may be imperative for optimal outcome.
Simpson
Joe Leigh
JL
Baylor College of Medicine, Houston, Texas 77030, USA.
de la Cruz
Felix
F
Swerdloff
Ronald S
RS
Samango-Sprouse
Carole
C
Skakkebaek
Niels E
NE
Graham
John M
JM
Hassold
Terry
T
Aylstock
Melissa
M
Meyer-Bahlburg
Heino F L
HF
Willard
Huntington F
HF
Hall
Judith G
JG
Salameh
Wael
W
Boone
Kyle
K
Staessen
Catherine
C
Geschwind
Dan
D
Giedd
Jay
J
Dobs
Adrian S
AS
Rogol
Alan
A
Brinton
Bonnie
B
Paulsen
C Alvin
CA
D035843:Biomedical Research; D005817:Genetic Counseling; D006801:Humans; D007361:Intelligence Tests; D007713:Klinefelter Syndrome / Q000235:genetics* / Q000523:psychology; D007804:Language Development; D008297:Male