Polymalformative syndrome characterized by short
stature (dwarfism), mental retardation, and skeletal anomalies.
Herrmann-Pallister Syndrome; Herrmann-Pallister-Opitz
First described in 1975 by J. Herrmann, P.D. Pallister, W. Tiddy, and J.M. Opitz in two
families with multiple affected members. The designation “KBG-Syndrome” reflects Opitz's
preference of using the initials of patients' last names.
To date, about 41 cases have been reported.
Autosomal dominant, but also autosomal recessive transmission has been
suspected in some cases.
These patients have short stature (often below the third percentile; particularly
short trunk, which may in part be due to anterior wedging and abnormal upper and lower
plates of the vertebrae) and typical facial features that may include brachycephaly,
hypertelorism, wide and bushy eyebrows, large prominent ears, anteverted nostrils
with small alae nasi, long philtrum, and
oligoand/or macrodontia. Cryptorchidism seems to be quite common in male patients. Other
features that have been described in some of the patients include low anterior and posterior
hairline, fused or wide upper central incisors, short metacarpalia and clinodactyly, accessory
cervical ribs, thoracic kyphosis, and cardiac defects (e.g., ventricular septal defect).
Mental retardation, however, is a constant finding and may be severe and accompanied by
seizures. Hypoplasia of the cerebellar vermis or the posterior fossa could be demonstrated
in some patients.
If kyphosis is severe, a chest radiograph should be obtained. Lung
function tests are most likely difficult to perform on these mentally delayed patients.
Echocardiography may not only be required to exclude structural cardiac lesions, but also to
determine the presence of signs of cor pulmonale. Central neuraxial anesthesia techniques
may be difficult to perform due to the vertebral anomalies. Patient cooperation could be
limited secondary to mental retardation. Sedative and/or anxiolytic premedication
and the presence of the primary caregiver for induction of anesthesia may be helpful.
Subacute bacterial endocarditis prophylaxis may be required.
Consider interactions of anesthetics with chronic anti-seizure therapy.
Bracanti F, D'Avanzo MG, Digilio MC, et al: KBG syndrome in a cohort of Italian
patients. Am J Med Genet 131A:144, 2004.
Smithson SF, Thompson EM, McKinnon AG, et al: The KGB syndrome. Clin Dysmorphol
Zollino M, Battaglia A, D'Avanzo MG, et al: Six additional cases of the KBG
syndrome: Clinical reports and outline of the diagnostic criteria. Am J Med Genet