[MIM 270 400]

Prevalence: 1/20,000 to 1/60,000. Autosomal recessive transmission of mutations of the DHCR7 gene on 11 q 12-13. This mutation produces a deficiency in 7-dehydrocholesterol reductase that causes a disturbance in the synthesis of cholesterol: low plasma cholesterol. The absence of endogenous cholesterol  synthesis during fetal life results in intrauterine growth retardation and a polymalformative syndrome. Two types, (classic) I and II (severe, with significant perinatal mortality).

Characteristics:

-        growth retardation

-        microcephaly with cerebral malformations: lissencephaly, hydrocephalus, agenesis of the corpus callosum

-        facial dysmorphism: micrognathia, cleft palate, small hard tongue, downslanting palpebral fissures, ptosis, narrow forehead

-        cardiac malformation

-        abnormalities of the extremities (syndactyly)

-        abnormalities of the external genitalia: hypospadias, sexual ambiguity

-        aggressive behaviour and self-harm.

Sometimes: pyloric stenosis, Hirchsprung disease, vesicoureteral reflux.

Anesthetic implications:

Difficult intubation. Gastroesophageal reflux. An endotracheal tube with a diameter smaller than recommended for the patient's age should be used from the outset. Two published cases of muscular rigidity with hyperthermia after halothane administration, but without signs of malignant hyperthermia or rhabdomyolysis. Since then, many cases of uneventful use of halogenated agents have been described.

References : 

-        Mizushima A, Satoyoshi M. 
Unusual responses of muscular rigidity and hypothermia to halothane and succinylcholine; a case report of Smith-Lemli-Opitz syndrome.
Masui 1988 ; 37 (9) : 1118-23

-        Choi PT, Nowaczyk MJ. 
Anesthetic considerations in Smith-Lemli-Opitz syndrome. 
Can J Anaesth 2000; 47:556-61.

-        Quezado ZMN, Veihmeyer J, Schwartz L, Nwokoro NA, Porter FD. 
Anesthesia and airway management of pediatric patients with Smith-Lemli- Opitz syndrome. 
Anesthesiology 2002; 97: 1015-9.

-        Petersen WC, Crouch ER. 
Anesthesia-induced rigidity, unrelated to succinylcholine, associated with Smith-Lemli-Opitz syndrome and malignant hyperthermia. 
Anesth Analg 1995; 80:606-8.

Updated: November 2024