American Journal of Medical Genetics 132A:144–151 (2005)

Characterization of Liver Involvement in Defects ofCholesterol Biosynthesis: Long-Term Follow-Up and ReviewMassimiliano Rossi,1 Pietro Vajro,1 Raffaele Iorio,1 Antonella Battagliese,1 Nicola Brunetti-Pierri,1

Gaetano Corso,2,4 Maja Di Rocco,5 Paola Ferrari,6 Francesco Rivasi,7 Raffaella Vecchione,3

Generoso Andria,1 and Giancarlo Parenti1*1Department of Pediatrics, Federico II University, Naples, Italy2Department of Biochemistry and Medical Biotechnology, Federico II University, Naples, Italy3Department of Pathology, Federico II University, Naples, Italy4Department of Biomedical Sciences, University of Foggia, Italy5Department of Pediatrics, Istituto G. Gaslini, Genova, Italy6Department of Pediatrics, University of Modena, Italy7Department of Pathology, University of Modena, Italy

Inborn defects of cholesterol biosynthesis are agroup of metabolic disorders presenting withmental retardation and multiple congenitalanomalies (MCA/MR syndromes). Functional andstructural liver involvement has been reported asa rare (2.5–6%) complication of the Smith–Lemli–Opitz syndrome (SLOS) (OMIM: #270400) and ithas not been fully characterized. Here, we reporton a long-term follow-up study of four patientswith SLOS, and one case with lathosterolosis(OMIM: #607330) who presented with liver diseaseand underwent an extensive diagnostic work-up.Reports of liver involvement in cholesterol bio-synthesis defects are reviewed. Two main differ-ent patterns of liver involvement emerged:progressive cholestasis, and stable isolated hyper-transaminasemia. In our series, the first patternwas found in two patients with SLOS and one withlathosterolosis, and the second in two SLOS cases.Cholestasis was associated with early lethalityand normal serum g-glutamyl-transferase (GGT)levels in SLOS, while possible prolonged survivaland high GGT levels were seen in lathosterolosis.Hepatic fibrosis was present in both conditions.Liver biopsy performed in one of our SLOSpatients with isolated hypertransaminasemia,showed only mild hydropic degeneration of thehepatocytes. The presence of liver involvement in16% of the SLOS patients diagnosed at our Centersuggests that this complication might have beenunderestimated in previously reported cases,possibly overshadowed by the severity of multiplemalformations. Fetal hepatopathy, cholestasis,and isolated hypertransaminasemia can occuralso in other disorders of cholesterol biosynthesis,such as mevalonic aciduria (OMIM: þ251170),desmosterolosis (OMIM: #602398), Conradi–

Hunermann syndrome (OMIM: #302960), Green-berg dysplasia (OMIM: #215140), and Pelger–Huethomozygosity syndrome (#169400). This group ofinherited disorders should be considered in thedifferential diagnosis of patients presenting withliver disease associated with developmental delayand/or multiple malformations. Periodic liverfunction evaluations are recommended in thesepatients. � 2004 Wiley-Liss, Inc.

KEY WORDS: Smith–Lemli–Opitz syndrome;lathosterolosis; cholesterol bio-synthesis defects; liver; cholesta-sis; gamma-glutamyl-transferase;GGT

INTRODUCTION

Inborn defects of cholesterol biosynthesis are a group ofmetabolic disorders presenting variably with mental retarda-tion, multiple congenital anomalies, and abnormal bone calci-fication, i.e., as MCA/MR syndromes [Kelley and Herman,2001]. The Smith–Lemli–Opitz syndrome (SLOS) (OMIM:#270400), due to 7-dehydrocholesterol reductase (DHCR7) de-ficiency, is the most frequent and best characterized conditionin this group of diseases, with an incidence of approximately1 in 40,000 liveborn infants. In this condition developmentalabnormalities may affect virtually all organs and systems, inmost instances with a severe impact on prognosis and qualityof life.

Lathosterolosis (OMIM: #607330), due to the deficiency of 3-b-hydroxysteroid-D5-desaturase (SC5D), the enzyme involvedin the metabolic step immediately upstream of DHCR7, wasrecently identified by our group [Brunetti-Pierri et al., 2002],and is also a MCA/MR syndrome. Only a single living patientaffected by this disorder is known; a second male patient wasdiagnosed post-mortem [Parnes et al., 1990; Krakowiak et al.,2003].

Functional and structural liver involvement is a knownmanifestation of SLOS [Kelley andHennekam, 2000] althoughit has not been fully characterized. It is possible that variableliver involvement may be overshadowed by the severity ofmalformations in SLOS and, possibly, other related disorders.Theaimof this study is to better characterize liver involvementin defects of cholesterol biosynthesis.Here,we report on a long-term follow-up of four SLOS patients and the living patientwith lathosterolosis, all presenting with signs of liver disease.We also reviewed the literature about liver involvement indefects of cholesterol biosynthesis. The presence of hepatic

Grant sponsor: Ministero dell’Istruzione, Universita e Ricerca;Grant number: PRIN 2002 prot. 2002068222_003.

*Correspondence to: Dr. Giancarlo Parenti, Department ofPediatrics, Federico II University, Naples, Italy.E-mail: parenti@unina.it

Received 22 July 2004; Accepted 28 August 2004

DOI 10.1002/ajmg.a.30426

� 2004 Wiley-Liss, Inc.

involvement in different defects of this pathway suggests a roleof cholesterol metabolism in the pathogenesis of liver diseases.

PATIENTS

Five patients with defects of cholesterol biosynthesispresented with abnormal liver function. Among 24 SLOSpatients diagnosed in theDepartment ofPediatrics, Federico IIUniversity, Naples, Italy in the last 10 years, clinically overt orsub-clinical liver disease were observed in 4. In all patients thediagnosis ofSLOSwassuspected on thebases of theassociationof typical facial features, limb anomalies including 2–3 toesyndactyly, and multiple malformations, and it was confirmedby gas chromatography–mass spectrometry plasma sterolprofiling, showing increased amounts of 7-dehydrocholesterol(Table IA). Molecular analysis of the DHCR7 gene was per-formed only in patient 4, who was a genetic compound for theR352W and IVS8-1G>C mutations [patient 8 in De Brasiet al., 1999]. A clinical severity score was assessed by previousstandards [Kelley andHennekam, 2000;Witsch-Baumgartneret al., 2000].

The patient with lathosterolosis (case 5) was identified bygas chromatography–mass spectrometry plasma and fibro-blast sterol profiling, showing increased amounts of lathosterol(Table IA). The diagnosis of lathosterolosis was confirmed bySC5Dassay in fibroblasts cultured in cholesterol-freemedium,and by mutational analysis of the SC5D gene [Brunetti-Pierriet al., 2002].

Patients were followed either at the Department of Pedia-trics, Federico II University of Naples, or in collaboration withlocal hospitals with periodic clinical assessment, routine bloodtests including liver function tests, liver ultrasound andbiopsy when appropriate, with follow-up periods ranging from2.5 months to 6 years (Table IB).

None of the patients was obese at the time of presentation ofliver involvement. In none of them drugs, possibly causinghepatotoxicity, were used. All SLOS patients had low plasmacholesterol levels. Cases 1 and 4 were supplemented with oralcholesterol (85–300 mg/kg/day of pure cholesterol added to anormal diet for age).

Liver function tests, imaging and histological findings aresummarized in Table IB.

Case 1

This girl with SLOS, presented at birth with malformations(Table IA) and neonatal jaundice, treated with phototherapy.Results of maternal screening tests for infectious diseases,including hepatitis B, were negative. At 2 weeks, aspartateamino transferase (AST) and alanine amino transferase (ALT)were normal (40 and 13U/L, respectively). Persistent jaundiceand pale stools were reported during the first months and, atthat time, physical examination showed a hard enlargedliver, mild splenomegaly, and undernourishment. Since theage of 2 months, blood chemistry tests showed raised levels ofAST (ranging from318 to 1,017U/L), ALT (197–521U/L), totaland conjugated bilirubin (9.60–9.70 mg/dl; 4.70–7.57 mg/dl, respectively), alkaline phosphatase (ALP) (1,162 U/L),whereas g-glutamyl-transferase (GGT) was normal (12 U/L)(Table IB). Alpha-fetoproteinwas greatly elevated (>100,000 ng/ml; normal range: <10). Raised white cell count (21,200–32,800/ml; neutrophils: 10,320–19,980/ml), platelets (470,000–1,002,000/ml) andmarkers of inflammation were also detected,as well as mild transient anemia at the age of 4 months(hemoglobin lowest level 8.6 g/dl). Serial blood cultures, sero-logy for toxoplasma, rubella, cytomegalovirus, herpes simplex,urinary cytomegalovirus, a-1-antitrypsin, immunoglobulins,lymphocyte subtyping, thyroid function tests, chromosomeanalysis, and screenings for commonmetabolic disorders were

negative or normal. Creatine kinase (CK) was normal, rulingout muscle-derived hypertransaminasemia.

Ultrasonography of liver showed an enlarged bright liverwith no other anomalies. Laparotomy showed a cirrhotic liverand intraoperative cholangiography demonstrated a normalbiliary tract.

Histologic studies showed a distorted hepatic architecturewith marked portal, periportal and pericellular fibrosis,bridging and nodular features, ductular proliferation, diffusegiant cell transformation, biliary pigment within hepatocytes,canaliculi and Kupffer cells, and hemosiderin granules inKupffer cells (Fig. 1).

Ursodeoxycholic acid supplementation (30 mg/kg/day), highcholesterol diet (85 mg/kg/day) and wide-spectrum antibiotictherapy were started at the age of 2 months. Despite loweringof total and direct bilirubin (3.9 mg/dl; 2.6 mg/dl, respectively),and amino transferases serum levels (AST: 135 U/L; ALT111 U/L) (Table IB), in the following weeks the patient’sgeneral conditions worsened progressively and she eventuallydied in another hospital at age 5 months.

Case 2

This girl with SLOS, was born at 36 weeks of gestation.Asphyxia and multiple severe malformations were noted(Table IA), as well as neonatal jaundice since the 2nd day oflife (total bilirubin: 14.3 mg/dl in the 3rd day of life), treatedwith phototherapy. In the following weeks, results of liverfunction tests were found to be abnormal (AST: 135–417 U/L;ALT: 198–337 U/L; total bilirubin: 7.99–8.59 mg/dl; conju-gated bilirubin: 2.6–3.5 mg/dl; ALP: 449–1200 U/L), exceptGGT levels (34 U/L) (Table IB). Transient thrombocytopenia(22,000/mm3) and anemia (hemoglobin 6.8 g/dl) were noted. Asepsis was diagnosed and treated with antibiotics. An abdo-minal ultrasound scan was normal at 11 days of life.

During the following month, a hard and enlarged liver wasnoted on clinical examination and abnormalities of liverfunction tests persisted. Blood cultures, standard karyotypewere negative or normal. Due to persistent vomiting andfeeding difficulties, parenteral nutrition was needed intermit-tently. No further investigations on liver involvement wereperformed as, due to the severe clinical conditions of thepatients, parents refused liver biopsy and a regular follow-up.The patient died at age 2.5 months.

Case 3

This girl with SLOS, presented with congenital anomaliesincluding severe heart malformations (atrioventricular canal,patent ductus arteriosus, hypoplastic pulmonary truncus)(Table IA). Neonatally amino transferases levels were normalfor age (AST: 39U/L; ALT: 76U/L). From the age of 1.5months,a persistent increase of AST (68–193 U/L) and ALT (108–690)was noted (Table IB). Due to heart malformation and general-ized seizures she was treated with dipyridamole and multi-drug anticonvulsant therapy (phenobarbital, clonazepam,ethosuximide). Since thebeginning of this therapeutic regimena slight increase of GGT andALPwas noted (35–178 and 418–702 U/L, respectively) with normal total bilirubin levels (0.3–0.4 mg/dl). These abnormalities were considered the result ofthe anticonvulsant therapy.

Since the age of 3 years liver ultrasonography showedhepatomegaly. Screening tests for common infectious diseases,including hepatitis A, B, and C, Epstein–Barr virus, toxoplas-ma, rubella virus, and cytomegalovirus,werenegative. Screen-ing tests for inborn metabolic disorders were also negative.Liver histology was normal, apart from slight hydropicdegeneration of some hepatocytes (Fig. 2). The patient died atage 6 years of heart failure.

Liver Disease in Cholesterol Biosynthesis Defects 145

TABLE

I.Manifestation

sin

OurPatien

ts

Patien

ts1

23

45

Diagnosis

SLOS

SLOS

SLOS

SLOS

Lathosterolosis

A:Clinicalfindingsandsterol

patternatdiagnosis

Clinicalfindings

Gen

der

Fem

ale

Fem

ale

Fem

ale

Male

Fem

ale

Dev

elop

men

taldelay

þþ

þþ

þMicrocephaly

þþ

þþ

þBrain

anom

alies

þþ

�þ

�Cataract/len

sop

acities

�þ

��

�Cleft

palate/bifiduvula

�þ

þþ

�Con

gen

italhea

rtdefect

þ�

þ�

�Pyloricsten

osis

�þ

�þ

�Ren

alanom

alies

��

��

þGen

italanom

alies

��

�þ

�Polydactyly

��

��

þToe

syndactyly

þþ

þþ

þCholestaticliver

disea

seþ

þ�

�þ

Mildly

raised

aminotransferases

��

þþ

�SLOSseverityscorea

89

64

Sterolpatternatdiagnosis

Cholesterol(m

g/dl)

924

21

33

170

7-deh

ydroch

olesterol(m

g/dl)

34

86

17

9�

Lathosterol(m

g/dl)

��

��

13

B:Liver

seru

mfunctiontests(rangeof

lowestandhighestvalues

mea

suredduringfollow

-up),im

aging,andhistology

Ageof

recruitmen

tBirth

Birth

Birth

5yea

rs1yea

rFollow-uplength

5mon

ths

2.5

mon

ths

6yea

rs2yea

rs4yea

rsLiver

functiontests

AST(tim

esUNL)

<1–14

2–6

<1-4

<1–2

3–8

ALT(tim

esUNL)

<1–6

2–4

<1–20

1–4

2–7

GGT(tim

esUNL)

<1

<1

�1–5b

<1

5–19

ALP(tim

esUNL)

�1–3

1–3

1–3b

<1

5–15

Totalbilirubin

(tim

esUNL)

3–9

2–8

<1

<1

<1–11

Directbilirubin

(tim

esUNL)

7–25

9–12

<1

<1

<1–35

Totalbileacid(tim

esUNL)

�1–3

NP

NP

NP

3–12

Quicktime%

42–66

NP

80-85

93–102

43–94

INR

1.74–1.31

1.04

NP

1.11–0.99

1.12–1.71

Liver

ultrasounds

Enlarged

brightliver

Enlarged

liver

cEnlarged

liver

Brightliver

Bilob

edgall-bladder

Liver

histology

Cirrh

osiswithportalperiportal

andpericellularfibrosis,

giantcells,

cholestasis

NP

Slighthydropic

hep

atocytes

changes;absence

ofsp

ecificlesion

s

NP

Portalfibrosis,

cholestasis

þ,present;�,absent;NP,not

perform

ed;UNL,upper

normallimitforage.

aScore

range:

0–20.

bCase

3wason

multi-dru

ganticonvulsanttherapywhen

GGTandALPlevelsweremea

sured.

c Detectedon

clinicalex

amination

only.

Case 4

This boywith SLOS, presented withmultiple anomalies anddevelopmental delay (Table IA).Mildly increased serumaminotransferases levels were noted since the age of 5 years, onfollow-up laboratory evaluation (AST: 35–91 U/L; ALT: 54–158 U/L). On physical examination liver size was normal.Serum markers of cholestasis were within the normal range(Table IB). Tests for commoncauses of hypertransaminasemia,including serologic tests for infectious diseases (toxoplasma,cytomegalovirus, Epstein–Barr virus, hepatitis A, B, and C),screening tests for celiac disease, serum copper and cerulo-plasmin, a-1-antitrypsin, anti-nucleus, anti-liver-kidneymicro-somes, and anti-smooth muscle autoantibodies, CK, serumimmunoglobulins were negative. Since the age of 7 years,abdominal ultrasound scans showed mild steatosis; AST wasnormal (45 U/L) and ALT was only slightly elevated (68 U/L).The patient was on a very high cholesterol supplementation(up to 300 mg/kg/day).

Case 5

This patient with lathosterolosis presented with multiplecongenital anomalies including minor facial anomalies, limbabnormalities, horseshoe kidneys, a ‘‘butterfly’’ vertebra, anddevelopmental delay (Table IA) [Brunetti-Pierri et al., 2002].Maternal serology, performed during pregnancy, ruled outcongenital cytomegalovirus, toxoplasma, rubella, hepatitis Band C, HIV, and syphilis. Neonatal jaundice was treated withphototherapy. Abnormal liver function was first documentedat 12 months on a follow-up laboratory evaluation, showingraised levels of amino transferases (AST: 262U/L; ALT: 188U/L), ALP (1,731 U/L), GGT (539 U/L), and total bile acids(52 mmol/L; normal range <16 mmol/L); at that time clottingtest (international normalized ratio, INR) was normal (1.13;normal range: 0.84–1.25) (Table IB). Total and direct bilirubinlevels were normal (0.97 and <0.3 mg/dl, respectively)(Table IB) as well as cholesterol levels (Table IA).

Results of screening tests for hepatitis B and C, Epstein–Barr virus, and Adenovirus were negative. Cyomegalovirusinfection, initially suspected based on a positive urinary cyto-megalovirus antigen at the age of 9months, was not confirmedby PCR analysis (performed at the age of 13 months andretrospectively on a neonatal Guthrie card), negative plasmacytomegalovirus antigen and specific IgM. Total immunoglo-bulins and lymphocyte subtyping were normal, as well asscreening for other possible causes of chronic liver diseaseincluding cystic fibrosis, celiac disease, and commonmetabolicdisorders. An abdominal ultrasound scan showed normal liversize and structure and a bilobed gallbladder with regular wallsand no gallstones.

A liver needle biopsy, performed at the age of 14 months,showed bile stasis, severe portal fibrosis, proliferation of bileducts, which were irregular and abnormally displaced aroundblood vessels resembling a ductal plate malformation; granu-locyte and monocyte cholangiolitis was evident; no inflam-mation was noted in the parenchyma (Fig. 3). Periportalhepatocytes had diffuse expression of biliary cytokeratin CK7.No viral inclusions or findings suggestive intracellular lipidstorage were noted.

Therapy with ursodeoxycholic acid (20 mg/kg/day) wasstarted at the age of 15 months. Nevertheless, in the followingyears, cholestasis and liver functionworsenedprogressively; atthe age of 5 years AST levels were 400 U/L, ALT 157 U/L, ALP

Fig. 1. Case 1. Surgical liver biopsy.A: Portal, periportal andpericellular fibrosiswith porto-portal bridging (CAB,�100).B:Giant cells, portal tractwithductular proliferation (CAB, �200).

Fig. 2. Case 3. Needle liver biopsy. Hepatic tissue without any evidentlesions, apart from slight hydropic degeneration of some hepatocytes (H&E,�200).

Liver Disease in Cholesterol Biosynthesis Defects 147

2704 U/L, GGT 317 U/L; total and direct bilirubin were 11.60and 10.40 mg/dl, respectively; total bile acids were>200 mmol/L; INR was 1.71; at that time plasma cholesterol andlathosterol levels (analyzed by gas chromatography–massspectrometry) were 250 and 25 mg/dl, respectively (Table IB).

DISCUSSION

We report a long-term follow-up of five unrelated patientswith SLOS and lathosterolosis, two different defects ofcholesterol biosynthesis. These metabolic disorders are char-acterized by disturbed morphogenesis affecting central ner-vous system, limbs, genitalia, and virtually all internal organs.Liver disease has been reported infrequently. Nevertheless,the severity of malformations may overshadow a liver involve-ment. A review showed that in a few studies of SLOS patients[Bialer et al., 1987; Curry et al., 1987; Pierquin et al., 1995;Cunniff et al., 1997; Ness et al., 1997; Nwokoro and Mulvihill,1997; Ryan et al., 1998;Herman, 2003] (Table II) inwhich liverdisease was reported, the frequency of this manifestationappeared low, with estimates of 2.5% [Cunniff et al., 1997], 5%[Herman, 2003], and 6% [Ryan et al., 1998]. Nevertheless,Nwokoro and Mulvihill [1997] reported a higher frequency,with three patients out of six examined showing mild andtransient hypertransaminasemia. Liver histological abnorm-alities were documented in a single patient with normal liverfunction [Pierquin et al., 1995] (Table IIA). In our study wefound 4 SLOS patients with abnormal liver function testsamong 24 SLOS cases diagnosed at our Center; the frequencyof liver involvement in our SLOS population appeared there-fore to be approximately 16%.

We also found liver disease in a patient with lathosterolosis.Lathosterolosis is a rare disorder that was identified recently[Brunetti-Pierri et al., 2002]. To date, only a second malepatienthasbeenreported [Parnesetal., 1990;Krakowiaketal.,2003] and, therefore, it is not possible to estimate the frequencyof liver involvement in this condition. Anyway, this patient,presenting with a more severe phenotype as compared to case5, did show signs suggesting cholestatic liver disease, inaddition to multiple facial, genital, and limb malformations,cataract, severe neurological signs and early death. Liverhistology showed fibrosis in portal and periportal areas, andlarge inclusions of lipids and mucopolysaccharides [Parneset al., 1990; Krakowiak et al., 2003]. Interestingly, lathoster-

olosis mice have enlarged liver and multiple malformations[Krakowiak et al., 2003].

The degree of hepatic involvement in our patients wasvariable, ranging from severe cholestasis (cases 1 and 2,accounting for 8% of the SLOS patients, and case 5 withlathosterolosis), to a mild/moderate increase of serum aminotransferases (cases 3 and 4; 8% of the SLOS patients). Severeprogressive cholestasiswas strikingand common inbothSLOSand lathosterolosis and, among SLOS patients, seemed morefrequently associated with severe phenotypes, as defined by avalidated severity score [Kelley and Hennekam, 2000; Witsch-Baumgartner et al., 2000], while isolated hypertransaminase-mia was associated with milder phenotypes.

GGT serum levels were normal in our two SLOS cases withsevere cholestatic liver disease and increased in the lathoster-olosis patient; these findings might be an interesting clue todifferential diagnosis between these disorders, which show asignificant clinical overlap.

Although progressive cholestasis has been occasionallyreported as a possible severe, life-threatening complication ofSLOS, to the best of our knowledge, a full hepatic histo-logical description has been published to date in only onebiochemically confirmed SLOS case [Ness et al., 1997]. Inour patients, histologic analysis showed fibrosis in both SLOSand lathosterolosis with cholestasis, fitting with previousobservations [Parnes et al., 1990; Ness et al., 1997]; it involvedboth portal spaces and the parenchyma in the formercondition, and particularly portal tracts in the latter. On theother hand, this is the first description of a liver biopsy in apatient with SLOS and isolated hypertransaminasemia,showing mild hydropic degeneration of the hepatocytes with-out fibrosis.

Common causes of liver disease or isolated hypertransami-nasemia were ruled out in our patients, based on theirbiochemical and immunological profile.Particularly, inpatient2 cholestasis associated with asphyxia and parenteral nutri-tion was excluded as these forms are usually characterized byraised GGT serum levels [Vajro et al., 1997; Forchielli andWalker, 2003], and we found normal GGT in case 2.

Two patients with SLOS were on oral cholesterol supple-mentation; although we noticed a decrease of liver enzymesserum levels after the start of therapy especially in case 1,overall this therapeutic regimen did not improve significantlythe patient’s prognosis.

Fig. 3. Case 5. Needle liver biopsy. A: Three portal tracts with severe fibrosis (CAB, �100). B: Portal fibrosis with ductular proliferation and mixedinflammatory infiltrate (H&E, �200).

148 Rossi et al.

TABLE

II.Types

ofOccurren

ceof

Liver

Involvem

entin

Defects

ofCholesterolBiosynthesis

A:Post-natalliver

disea

se

Liver

disea

seSLOS

Lathosterolosis

Mev

alonic

aciduria

Progressiveintra-hep

aticch

olestasis

þþ

þHep

atomeg

aly

þþ

þSplenom

egaly

þþ

þRep

ortedhistologicalfindings

Pericellularfibrosis/ea

rlyseptalfibrosis

þ�

�Portal/periportalfibrosis

þþ

þGiantcells

þ�

�In

crea

sedex

tra-m

edullary

hem

atopoiesis

þ�

þIron

inhep

atocytes/Kupffer

cells/portaltracts

þþ

�Bileduct

proliferation

þþ

�Fibroticex

tra-hep

aticbileducts

þa

��

Cholangiolitis

�þ

�Mucopolysa

ccharideandlipid

inclusion

s�

þ�

Hyp

ertransa

minasemia

withou

tch

olestasis

þ�

þHep

atomeg

aly

þ�

þSplenom

egaly

��

þRep

ortedhistologicalfindings:

Slighthydropichep

atocytesch

anges,absence

ofev

iden

tsp

ecificlesion

sþ

��

Asymptomaticliver

involvem

ent

þ�

�Rep

ortedhistologicalfindings

Slightfibrosis

þ�

�Parench

ymalinclusion

s(lipofuscins)

þ�

�In

crea

sednumber

ofperox

ysomes

þ�

�Liver

and/orbiliary

tract

malformation

sþ

þ�

Absentliver

lobulation

þa

��

Extra-hep

aticbiliary

atresia

þa

��

Atretic

gall-bladder

þ�

�Bilob

edgall-bladder

�þ

�Gallston

esþ

��

Referen

ces

Case

1–4:Bialeret

al.[1987],Curry

etal.[1987],Pierquin

etal.[1995],

Cunniffet

al.[1997],Nesset

al.

[1997],Nwok

oroandMulvihill

[1997],Ryanet

al.[1998]

Case

5:P

arn

eset

al.[1990],

Bru

netti-Pierriet

al.

[2002],Krakow

iaket

al.

[2003]

Hoffm

annet

al.[1993],

Hinsonet

al.[1998],

Clayton[2003]

B:Pre-natalliver

disea

seSLOS

Desmosterolosis

Con

radi–

Hunermann

Green

bergdysp

lasiab

Hydrops

þ�

�þ

Hep

atomeg

aly

�þ

þþ

Splenom

egaly

�þ

��

Rep

ortedhistologicalfindings:

Portalfibrosis

�þ

��

Excessiveex

tra-m

edullary

hem

atopoiesis

�þ

�þ

Referen

ces

Clayton[2003]

Fitzp

atricket

al.[1998],

Clayton[2003]

Clayton[2003]

Clayton[2003],Oosterw

ijk

etal.[2003]

þ,reported;�,not

reported.

aFea

ture

reportedon

lyin

SLOScase

not

bioch

emicallyconfirm

ed.

bIsolatedhep

atomeg

aly

hasbeenreported,post-natally,alsoin

onecase

ofPelger

–Huethom

ozygosity,allelic

toGreen

bergdysp

lasia[O

osterw

ijket

al.,2003].

A variable functional involvement of the liver was found inother disorders of cholesterol biosynthesis. It is very wellknown that isolated hypertransaminasemia and hepatome-galy are part of the phenotype of mevalonic aciduria (OMIM:þ251170), due to mevalonate kinase deficiency, together withrecurrent fever, splenomegaly, and gastrointestinal symptoms[Hoffmann et al., 1993]. Severe progressive cholestasis hasbeen reported as well [Hinson et al., 1998] (Table IIA).Hepatomegaly or liver dysfunction with post-natal or evenpre-natal onset was reported in desmosterolosis (OMIM:#602398) due to 24-dehydrocholesterol reductase deficiency,Conradi–Hunermann syndrome (OMIM: #302960) due to 3-b-hydroxysteroid-D8,D7-isomerase deficiency, Greenberg dys-plasia (OMIM: #215140) and the Pelger–Huet homozygositysyndrome (#169400) bothof themdue tomutations in the laminB receptor gene (Table IIA,B) [Fitzpatrick et al., 1998; Clayton,2003; Oosterwijk et al., 2003].

The pathogenesis of liver damage in SLOS and lathoster-olosis is unclear. In SLOS, insufficient cholesterol availabilityfor cell membranes may cause cellular dysfunction and multi-organ failure including liver disease. Alternatively, very youngseverely affected SLOS children may produce and secreteinadequate quantities of normal bile acids, resulting in severecholestasis and reduced intestinal cholesterol absorption.

The differential diagnosis of cholestasis with normal GGT andgiant cells on histological liver examination, includes the ARCsyndrome (OMIM: #208085) due to mutations of the VPS33Bgene, defects of bile acids transport, such as progressive familialintra-hepatic cholestasis (PFIC) 1 and 2 due to mutations of theATP8B1 and ABCB11 genes, respectively (OMIM: #211600 and#601847, respectively), and a few conditions characterized byabnormal bile acids metabolism such as primary defects of bileacids biosynthesis (PFIC 4, due to 3-b-hydroxy-D-5-C27-steroidoxidoreductase deficiency, OMIM: #607765) and generalizeddefects of peroxisomal biogenesis [Bove et al., 2000; Elferink,2003; Gissen et al., 2004]. Our cases 1 and 5 during follow-updevelopedhigh levels of total serumbile acids, likely secondary tobile stasis (Table IB). Itmightbe interesting to emphasize thatanabnormal bile acid biosynthesis and metabolism has beendemonstrated in a rat model of severe SLOS [Honda et al.,1999], and abnormal bile acid species have been demonstrated inSLOSpatients [NatowiczandEvans,1994;Steineretal., 2000]. Ithas beenhypothesized in the past that thesemetabolites, even insmall concentrations, may contribute to liver dysfunction inSLOS patients [Honda et al., 1999].

Over time, the patient with lathosterolosis developed highlevels of serum cholesterol, as reported in other congenitalcholestasis conditions with high GGT levels, such as PFIC3(OMIM: #602347), due to ABCB4 mutations, and Alagillesyndrome (OMIM: #118450), due to Jagged 1 mutations[Elferink, 2003]. It might be interesting to emphasize someclinical similarities between our patient with lathosterolosisand Alagille syndrome, i.e., cholestatic liver disease and a‘‘butterfly’’ vertebra. Moreover, although bile duct paucity isthe typical histological picture found in Alagille syndrome,duct proliferation has been reported as well [Deutsch et al.,2001]. Finally, the Sonic Hedgehog (SHH) protein signaltransduction pathway, which is impaired in cholesterolbiosynthesis defects [Kelley and Herman, 2001], is linked tothe NOTCH/Jagged signaling pathway [Frezal, 1998; Lopezet al., 2003]. These observations suggest a possible pathogeniclink for liver involvement in these conditions. Hence, furtherstudies are necessary to clarify the pathogenic mechanisms ofliver diseases in cholesterol biosynthesis defects.

ACKNOWLEDGMENTS

We are thankful to Dr. M.Witsch-Baumgartner, Institute ofMedical Biology and Human Genetics, Innsbruck, Austria, for

identifying the mutation IVS8-1G>C in case 4, to Dr. L.Zelante, CSS-IRCCS, S. Giovanni Rotondo (FG), Italy, forproviding some clinical information about case 3.

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