A rare chromosomal disorder manifested by the presence
of five X chromosomes leading to short stature, mental retardation, fifth
finger clinodactyly, short neck, microcephaly, cardiac anomalies
(ventricular septal defect, atrial septal defect, patent ductus arteriosus),
and horseshoe kidneys. Onset is during childhood.
XXXXX Syndrome; Pentasomy X; 49XXXXX Syndrome.
First described by Kesaree and Wooley in 1963.
The X chromosomes are of maternal origin. Risk
factors for females only. The incidence is rare, about 25 cases reported.
The pathogenesis is believed to be a result of successive nondisjunctive
meiotic divisions within the mother.
Prenatal onset growth deficiency with failure to
thrive and short stature. Microcephaly with upward slant of palpebral
fissures and hypertelorism. Seizure activity has been reported in 20% of patients
without abnormal brain function (MRI and EEG). Low nasal bridge, short neck. Small hands
with clinodactyly of the fifth finger. Forty percent of patients are known to have congenital heart defect: ventricular septal
defect, conotruncal or patent ductus arteriosus. Premature loss of deciduous teeth. Moderate to severe
mental retardation. Occasional findings include coloboma of the iris, myopia,
micropthalmus, and optic nerve hypoplasia (15%). Macroglossia, cleft palate,
micrognathia, low-set ears, club feet, multiple joint dislocation, renal dysplasia, and
horseshoe kidney (10%). Usually associated with equinovarus, overlapping toes, multiple joint
dislocations (shoulder, elbow, hip, wrist, and finger), and radioulnar synostosis.
Check renal function and cardiac
anatomy. A cardiac echocardiography might be indicated.
The association of micrognathia with
macroglossia could lead to difficult airway management. Careful positioning
to avoid joint dislocation. Specific considerations will be dictated by the
cardiac and renal anomalies.
Antibioprophylaxy may be indicated in case of cardiac
Linden MG, Bender BG, Robinson A: Sex chromosome tetrasomy and pentasomy.