PatientPlus articles are written for doctors and so the language can be technical. However, some people find that they add depth to the articles found in the other sections of this website which are written for non-medical people.

Laurence-Moon Syndrome

Synonyms: Laurence Moon Biedel Syndrome, Laurence-Moon Bardet-Biedel syndrome, Adipogenital-Retinitis Pigmentosa Syndrome. LM syndrome. LMBB syndrome

The features of the condition are mental retardation, pigmentary retinopathy, hypogenitalism, and spastic paraplegia.¹ It has much in common with Bardet-Biedel syndrome and there is some debate to whether they are distinct conditions or variations on the same syndrome.² For this reason it is sometimes known as the Laurence-Moon-Biedel Syndrome or the Laurence-Moon-Bardet-Biedel Syndrome.

Although many authors and publications are ambivalent or supportive of the concept of a unified disease the United Medical Language System is quite strident about there being two distinct conditions. It states, "Laurence-Moon-Biedel syndrome and Laurence-Moon-Biedel-Bardet syndrome are no longer considered as valid terms in that patients of Laurence and Moon had spastic paraplegia but no polydactyly and obesity which were the key elements in the Bardet and Biedel patients. Bardet-Biedel syndrome is a separate entity."³

Epidemiology: It is a rare autosomal recessive disease that affects about 1 in 100,000 babies. The precise nature of the genetic defect is far from clear. If it is the same as Bardet-Biedel syndrome, there are 9 different gene loci that have been identified. Both conditions appear to be unusually common in Kuwait and consanguinity is thought to be important in this.⁴

Presentation: The question of whether this is one syndrome or two makes the literature very confusing, not least with regard to features of the disease. Heterozygous carriers are more likely to be obese.⁵

Very common features include:

• General obesity
• Hypogonadism, both male and female. Some evidence suggests that the pituitary gland is not the source of the failure⁶ although others have found an empty sella syndrome.⁷
• Mental retardation
• Syndactyly of fingers and polydactyly of fingers are said to be features of Bardet-Biedl syndrome and not Laurence Moon syndrome
• Progressive loss of vision due to retinitis pigmentosa. The ocular disease presents early, the prognosis for visual function is poor and the fundal features are atypical and varying.⁸
• Abnormal antitragus. This is a prominence on the lower posterior portion of the concha of the external ear opposite the tragus

Common features include:

• Sensori-neural deafness causing childhood deafness
• Small penis
• Chronic renal failure. Renal disease contributes significantly to the reduction in life expectancy in this disease.⁹ There have been a number of reports of renal transplantation being followed by morbid obesity.¹⁰
• Short stature, possibly related to growth hormone deficiency.¹¹
• Undescended or ectopic testes

Occasional features include:

• Ataxia and nystagmus
• Brachycephaly
• Diabetes mellitus
• Congenital cardiac defects
• Low set ears
• Spastic paraplegia of the lower part of the body

Investigations: There is no specific laboratory test for the disease but diagnosis is based on clinical features, perhaps in the presence of a family history.

The opinion of an ophthalmologist should be sought. There should be screening for deafness and renal function should be monitored.

Differential diagnosis: Bardet-Biedel syndrome which has characteristic features of severe retinal dystrophy, dysmorphic extremities, obesity, renal abnormalities, and (in male patients only) hypogenitalism. Mental retardation, polydactyly, and hypogonadism in female patients are not necessarily present.¹² There are a number of syndromes of pigmentary retinopathy and, in many, combined with deafness, hypogonadism, and/or mental retardation.¹³

Management:

• Obesity requires attention to diet. Helping patients to lose weight is difficult but valuable
• Chronic renal failure may be better managed by dialysis than transplantation in view of the risk of morbid obesity
• Hormone deficiencies may be treated by hormone replacement
• Learning difficulties require early diagnosis and remedial attention. There is a report of left temporal and parietal lobe hypoplasia and suggestion that intensive speech and language therapy with physiotherapy is beneficial.¹⁴ Hearing problems may add to learning difficulties as does failing vision.
• Retinitis pigmentosa can present as night blindness, followed by tunnel vision and ultimately blindness. Education may need to account for failing vision and ultimately blindness

Prognosis: The course can be quite variable but tends to run true in families. Renal disease is the major cause of early death.

Prevention: There is no test for antenatal detection

References:

1. OMIM Laurence Moon syndrome 245800
2. OMIM Bardet-Biedel syndrome 209900
3. United Medical Language System Laurence Moon syndrome
4. Farag TI, Teebi AS; Bardet-Biedl and Laurence-Moon syndromes in a mixed Arab population.;Clin Genet. 1988 Feb;33(2):78-82.[abstract]
5. Croft JB, Morrell D, Chase CL, et al; Obesity in heterozygous carriers of the gene for the Bardet-Biedl syndrome.;Am J Med Genet. 1995 Jan 2;55(1):12-5.[abstract]
6. Whitaker MD, Scheithauer BW, Kovacs KT, et al; The pituitary gland in the Laurence-Moon syndrome.;Mayo Clin Proc. 1987 Mar;62(3):216-22.[abstract]
7. Soliman AT, Rajab A, AlSalmi I, et al; Empty sellae, impaired testosterone secretion, and defective hypothalamic-pituitary growth and gonadal axes in children with Bardet-Biedl syndrome.;Metabolism. 1996 Oct;45(10):1230-4.[abstract]
8. Riise R, Andreasson S, Wright AF, et al; Ocular findings in the Laurence-Moon-Bardet-Biedl syndrome.;Acta Ophthalmol Scand. 1996 Dec;74(6):612-7.[abstract]
9. Riise R; The cause of death in Laurence-Moon-Bardet-Biedl syndrome.;Acta Ophthalmol Scand Suppl. 1996;(219):45-7.[abstract]
10. Collins CM, Mendoza SA, Griswold WR, et al; Pediatric renal transplantation in Laurence-Moon-Biedl syndrome.;Pediatr Nephrol. 1994 Apr;8(2):221-2.[abstract]
11. Chalvon-Demersay A, Tardieu M, Crosnier H, et al; ;Arch Fr Pediatr. 1993 Dec;50(10):859-62.[abstract]
12. Green JS, Parfrey PS, Harnett JD, et al; The cardinal manifestations of Bardet-Biedl syndrome, a form of Laurence-Moon-Biedl syndrome.;N Engl J Med. 1989 Oct 12;321(15):1002-9.[abstract]
13. Cantani A, Bellioni P, Bamonte G, et al; Seven hereditary syndromes with pigmentary retinopathy. A review and differential diagnosis.;Clin Pediatr (Phila). 1985 Oct;24(10):578-83.[abstract]
14. Chen CL, Chung CY, Cheng PT, et al; Linguistic and gait disturbance in a child with Laurence-Moon-Biedl syndrome: left temporal and parietal lobe hypoplasia.;Am J Phys Med Rehabil. 2004 Jan;83(1):69-74.[abstract]
15. Laurence JZ, Moon RC, Four cases of retinitis pigmentosa occurring in the same family and accompanied by general imperfection of development. Ophthal. Rev. 1866 2: 32-41
16. Hutchinson J On retinitis pigmentosa and allied affections, as illustrating the laws of heredity. Ophthal. Rev. 1: 2-7 and 26-30, 1882.
17. Hutchinson J Slowly progressive paraplegia and disease of the choroids with defective intellect and arrested sexual development. Arch. Surg. 11: 118-122, 1900.
18. Solis-Cohen, S.; Weiss, E. :Dystrophia adiposogenitalis with atypical retinitis pigmentosa and mental deficiency: the Laurence-Biedl syndrome. Am. J. Med. Sci. 169: 489-505, 1925.

Internet:

• The Laurence-Moon-Bardet-Biedl Society UK. Offers honest and practical help and advice
• LMBB Society What the teacher of a child with LMBB Syndrome should know

History:It was first described by Laurence and Moon in 1868.¹⁵ The disease was further described by Hutchinson in 1882¹⁶ and 1900.¹⁷ Solis-Cohen and Weis considered that the condition was identical with Bardet Biedl syndrome in 1925.¹⁸ Today opinion seems divided.

• John Zachariah Laurence was a British ophthalmologist, born 1830 and died 1974. He was a founder of the South London Ophthalmic Hospital, later known as the Royal Eye Hospital
• Robert Charles Moon was born in Brighton in 1844 and qualified in London but emigrated to the USA in 1879, having been a surgeon at the South London Ophthalmic Hospital. He worked in Philadelphia and died in 1914
• Arthur Biedl was an endocrinologist born 1869 in Hungary but qualified in Vienna and later became professor at the Institute of Pathology in Vienna. He died in 1933
• Georges Louis Bardet was a French physician born 1885. Very little is known about him, not even his date of death

Acknowledgements EMIS is grateful to the Mentor authoring team for writing this article. The final copy has passed peer review of the independent Mentor GP authoring team. ©EMIS 2006.

Last issued 05 Jul 2006