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Aubry RL, Innes AM, Haber RM. Syndromic or non-syndromic congenital ichthyosis? A case report of two brothers with ichthyosis but microphthalmia and blindness in only one brother. SAGE Open Med Case Rep 2024; 12:2050313X241231386. [PMID: 38333515 PMCID: PMC10851717 DOI: 10.1177/2050313x241231386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/11/2023] [Indexed: 02/10/2024] Open
Abstract
We present the cases of two brothers with ichthyosis, born to consanguineous parents, with the eldest having extracutaneous manifestations in the form of microphthalmia and corneal opacities causing complete blindness. Initially, we were faced with the question of whether the phenotype in this family was due to the effects of a single pleiotropic, presumably autosomal recessive gene manifesting as a syndromic form of ichthyosis, or whether there were multiple causal genes, and the ichthyosis was non-syndromic. Ultimately, clinical follow-up of the family, combined with research-based exome sequencing established a diagnosis of NIPAL4 autosomal recessive congenital ichthyosis in both brothers, but the ocular abnormalities causing blindness in the older brother were due to coexisting autosomal recessively inherited loss of function mutations in peroxidasin, the latter finding also seen in a sister unaffected by ichthyosis.
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Affiliation(s)
- Rachel L Aubry
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - A. Micheil Innes
- Department of Medical Genetics, Alberta Children’s Hospital, Calgary, AB, Canada
| | - Richard M Haber
- Richmond Road Diagnostic and Treatment Centre (RRDTC), Calgary, AB, Canada
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2
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Hassan A, Mir YR, Kuchay RAH. Ocular findings and genomics of X-linked recessive disorders: A review. Indian J Ophthalmol 2022; 70:2386-2396. [PMID: 35791118 PMCID: PMC9426149 DOI: 10.4103/ijo.ijo_252_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Advent of new sequencing technologies and modern diagnostic procedures has opened the door for a deeper understanding of disorders about which little was known previously. Discovery of novel genes, new genetic variants in previously known genes and better techniques of functional validation has immensely contributed to unraveling the molecular basis of genetic disorders. Availability of knockout animal models like the zebrafish and gene editing tools like CRISPR-Cas9 has elucidated the function of many new genes and helped us to better understand the functional consequences of various gene defects. This has also led to better diagnosis and therapeutic interventions. In this context, a good body of research work has been done on X-linked recessive disorders with ocular findings. This review will focus on ocular and genetic findings of these rare disorders. To our knowledge, this is the first comprehensive review encompassing ocular and genomic spectrum of X-linked recessive disorders.
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Affiliation(s)
- Asima Hassan
- Department of Health and Medical Education, Srinagar, Jammu and Kashmir, India
| | - Yaser R Mir
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
| | - Raja A H Kuchay
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
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Limbal Stem Cell Dysfunction in Ichthyosis Follicularis, Alopecia, and Photophobia Syndrome. Cornea 2021; 39:1321-1324. [PMID: 32482964 DOI: 10.1097/ico.0000000000002393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe the presentation and management of limbal stem cell dysfunction in ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome. METHODS A retrospective case report. RESULTS A 6-day-old male infant was diagnosed with IFAP syndrome based on family history and a mutation detected in the MBTPS2 gene. Initial examination showed hyperkeratotic eyelids, madarosis, and lagophthalmos, but otherwise clear corneas. He developed bilateral central corneal epithelial defects spontaneously 6 months later, which were managed with aggressive lubrication, prophylactic antibiotics, and bilateral permanent lateral tarsorrhaphies at 7 months of age. During the procedure, the patient was noted to have bilateral limbal thickening, peripheral corneal pannus with underlying stromal scarring, and late fluorescein staining of the corneal surface. Anterior segment optical coherence tomography demonstrated a significantly abnormal and hyperreflective epithelial surface overlying a thinned corneal stroma, suggestive of limbal stem cell dysfunction. The corneal surface was maintained with lubrication and tarsorrhaphy and has remained stable since. CONCLUSIONS The progressive conjunctivalization, spontaneous epithelial defects, and anterior segment optical coherence tomography features are highly suggestive of limbal stem cell dysfunction in IFAP syndrome. Optimizing the ocular surface is of importance in the management of children with this rare disease.
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Irurzun I, Natale MI, Agostinelli ML, Lamberti M, Montero D, Granda C, Mássimo JA, Manzur GB, Valinotto LE. Ichthyosis follicularis, atrichia and photophobia (IFAP) and hereditary mucoepithelial dysplasia: Two syndromes that share a common clinical spectrum. Pediatr Dermatol 2021; 38:568-574. [PMID: 33742461 DOI: 10.1111/pde.14560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ichthyosis follicularis, atrichia and photophobia syndrome (IFAP) is an X-linked inherited disease caused by pathogenic variants in the gene encoding the membrane-bound transcription factor peptidase, site 2 (MBTPS2). Clinical presentation includes ichthyosis follicularis, alopecia, photophobia and developmental delay. Hereditary mucoepithelial dysplasia (HMD) is a dominantly inherited disease characterized by keratitis, non-scarring alopecia, skin lesions including follicular keratosis, perineal erythema, and mucosal involvement. Recently, variants in SREBF1, a gene coding for a transcription factor related to cholesterol and fatty acid synthesis, have been associated with the disease. These two syndromes share a common clinical spectrum. Here, we describe an IFAP syndrome patient with a novel variant in the MBTPS2 gene and an HMD patient with a previously reported variant in the SREBF1 gene. In addition, we present a review of the literature describing the triad characterized by non-scarring alopecia, keratosis follicularis, and ocular symptoms common in both IFAP and HMD patients to raise awareness of these underdiagnosed diseases. We also highlight the subtle differences in clinical presentation between the two disorders to better enable differentiation.
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Affiliation(s)
- Inés Irurzun
- Dermatology Unit, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Mónica I Natale
- Center in Investigation of Genodermatosis and Epidermolysis Bullosa (CEDIGEA), University of Buenos Aires, Buenos Aires, Argentina
| | | | - Magdalena Lamberti
- Dermatology Unit, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Dolores Montero
- Dermatology Unit, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Cecilia Granda
- Pathological Anatomy, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - José A Mássimo
- Dermatology Unit, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Graciela B Manzur
- Dermatology Unit, Hospital de Niños Dr. Ricardo Gutiérrez, Buenos Aires, Argentina.,Center in Investigation of Genodermatosis and Epidermolysis Bullosa (CEDIGEA), University of Buenos Aires, Buenos Aires, Argentina
| | - Laura E Valinotto
- Center in Investigation of Genodermatosis and Epidermolysis Bullosa (CEDIGEA), University of Buenos Aires, Buenos Aires, Argentina.,National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
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Bains A, Vedant D, Verma A, Bhardwaj A, Nalwa A. Ichthyosis Follicularis, Alopecia, and Photophobia (IFAP) Syndrome: A Case Report and Review of Cases Reported from India. Indian Dermatol Online J 2019; 10:686-691. [PMID: 31807449 PMCID: PMC6859747 DOI: 10.4103/idoj.idoj_19_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome is characterized by the triad of follicular keratotic papules, total to subtotal alopecia, and photophobia. We hereby report a case of IFAP syndrome in a 1-year-old boy who presented with all these classical features along with hyperkeratotic plaques over knees, plantar keratoderma, and umbilical hernia. Also, literature review of cases reported from India is being presented.
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Affiliation(s)
- Anupama Bains
- Department of Dermatology, Venereology and Leprology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh, India
| | - Deepak Vedant
- Department of Pathology, AIIMS Jodhpur, Rajasthan, India
| | - Anurag Verma
- Department of Dermatology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh, India
| | - Abhishek Bhardwaj
- Department of Dermatology, Venereology and Leprology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh, India
| | - Aasma Nalwa
- Department of Pathology, AIIMS Jodhpur, Rajasthan, India
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6
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Chen F, Wang J, Yao Z, Li M. A novel MBTPS2 start codon mutation causes a mild ichthyosis follicularis with atrichia and photophobia phenotype. Clin Exp Dermatol 2019; 45:505-507. [PMID: 31646662 DOI: 10.1111/ced.14114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 08/14/2019] [Accepted: 09/11/2019] [Indexed: 11/29/2022]
Affiliation(s)
- F Chen
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - J Wang
- Department of Dermatology, Henan Provincial People's Hospital, Zhengzhou, China
| | - Z Yao
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - M Li
- Department of Dermatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Jiang Y, Jin H, Zeng Y. A novel mutation in MBTPS2 causes ichthyosis follicularis, alopecia, and photophobia syndrome. Mol Genet Genomic Med 2019; 7:e812. [PMID: 31215178 PMCID: PMC6687642 DOI: 10.1002/mgg3.812] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022] Open
Abstract
Background The ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome is a rare X‐linked genodermatosis characterized by noninflammatory spiny follicular hyperkeratosis, severe photophobia, and non‐scarring alopecia with variable severities. IFAP syndrome results from mutations in the gene encoding the membrane‐bound transcription factor peptidase, site 2 (MBTPS2). Methods We present an 11‐year‐old male with typical clinical features of IFAP syndrome, including diffuse follicular hyperkeratosis, alopecia, photophobia, psoriasiform plaques, short statue, nail dystrophy, mental retardation, and seizures. Results A novel missense mutation (NM_015884.4: c.1298T > C; NP_056968.1: p. L433P) in the membrane‐bound transcription factor peptidase, site 2 gene (MBTPS2) was identified in our patient. The heterozygous MBTPS2 mutation was identified in his mother but not his father. Conclusion This study demonstrated a novel MBTPS2 mutation in a patient with IFAP syndrome and thus expands the known MBPTS2 molecular repertoire.
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Affiliation(s)
- Yanyun Jiang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hongzhong Jin
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yueping Zeng
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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8
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Affiliation(s)
- Arif O Khan
- a Eye Institute, Cleveland Clinic Abu Dhabi , Abu Dhabi , United Arab Emirates
- b Department of Ophthalmology , Cleveland Clinic Lerner College of Medicine of Case Western University , Cleveland , OH , USA
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Malhotra R, Hernández-Martın A, Oji V. Ocular manifestations, complications and management of congenital ichthyoses: a new look. Br J Ophthalmol 2017; 102:586-592. [DOI: 10.1136/bjophthalmol-2017-310615] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 02/04/2023]
Abstract
Congenital ichthyoses (CI) are rare genetic skin keratinisation diseases characterised by generalised scaling and a variable degree of erythema and hyperkeratosis. Ocular involvement includes the eyelids, conjunctiva and all layers of the cornea. Ophthalmic input should include regular slit lamp review with the primary aim to prevent a corneal epithelial defect, secondary bacterial infection, scarring or perforation. This review highlights the current literature regarding ophthalmic findings and management of CI.
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A Case of IFAP Syndrome with Severe Atopic Dermatitis. Case Rep Med 2015; 2015:450937. [PMID: 25685152 PMCID: PMC4320795 DOI: 10.1155/2015/450937] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/19/2014] [Accepted: 11/23/2014] [Indexed: 11/17/2022] Open
Abstract
Introduction. The IFAP syndrome is a rare X-linked genetic disorder characterized by the triad of follicular ichthyosis, atrichia, and photophobia. Case Report. A three-month-old Caucasian, male patient was observed with noncicatricial universal alopecia and persistent eczema from birth. He had dystrophic nails, spiky follicular hyperkeratosis, and photophobia which became apparent at the first year of life. Short stature and psychomotor developmental delay were also noticed. Histopathological examination of skin biopsy on left thigh showed epidermis with irregular acanthosis, lamellar orthokeratotic hyperkeratosis, and hair follicles fulfilled by parakeratotic hyperkeratosis. The chromosomal study showed a karyotype 46, XY. Total IgE was 374 IU/mL. One missense mutation c.1360G>C (p.Ala454Pro) in hemizygosity was detected on the MBTPS2 gene thus confirming the diagnosis of IFAP syndrome. Conclusions. We describe a boy with a typical clinical presentation of IFAP syndrome and severe atopic manifestations. A novel missense mutation c.1360G>C (p.Ala454Pro) in MBTPS2 gene was observed. The phenotypic expression of disease is quantitatively related to a reduced function of a key cellular regulatory system affecting cholesterol and endoplasmic reticulum homeostasis. It can cause epithelial disturbance with failure in differentiation of epidermal structures and abnormal skin permeability barrier. However, no correlation phenotype/genotype could be established.
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Naiki M, Mizuno S, Yamada K, Yamada Y, Kimura R, Oshiro M, Okamoto N, Makita Y, Seishima M, Wakamatsu N. MBTPS2 mutation causes BRESEK/BRESHECK syndrome. Am J Med Genet A 2011; 158A:97-102. [DOI: 10.1002/ajmg.a.34373] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 10/17/2011] [Indexed: 12/20/2022]
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Alshami M, Bawazir MA, Atwan AA. Photoletter to the editor: A new variant of ichthyosis follicularis with alopecia and photophobia (IFAP) syndrome with coexisting psoriasiform lesions and palmoplantar keratoderma. IFAP-PPK syndrome? J Dermatol Case Rep 2011; 5:14-6. [PMID: 21886760 DOI: 10.3315/jdcr.2011.1064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 03/03/2011] [Indexed: 11/11/2022]
Abstract
IFAP is an acronym for a rare congenital ectodermal disorder characterized by ichthyosis follicularis, alopecia and photophobia. A recessive X-linked mode of inheritance was initially proposed but recent reports in girls suggested genetic heterogeneity of this syndrome. We herein describe a 1-year-old boy with clinical features typical of IFAP syndrome plus psoriasis-like lesions and palmoplantar keratoderma (PPK).
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Affiliation(s)
- Mohammad Alshami
- Department of Dermatology, Kuwait University Hospital, Sana'a University, P.O. Box 1950, Sana'a, Yemen
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13
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Ichthyosis follicularis, alopecia, and photophobia syndrome: a case report and a pathological insight into pilosebaceous anomaly. Am J Dermatopathol 2011; 33:403-6. [PMID: 21242756 DOI: 10.1097/dad.0b013e3181e8b562] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome (OMIM 308205) is an extremely rare X-linked oculocutaneous genetic disorder characterized by follicular keratotic papules, total to subtotal alopecia, and photophobia. Previous reports depicted the histopathological features of affected skin lesions, represented by marked follicular plugging and hypoplastic pilosebaceous structures. However, past studies provided limited pathological information of pilosebaceous unit anomaly. Here, we report a 3-year-old boy's case with this uncommon condition. In this case, scalp biopsy samples were processed by both vertical and transverse sectioning techniques, which enabled a more detailed and quantitative pathological analysis of pilosebaceous structures. In vertical slices, miniaturized anagen hair follicles with characteristic follicular plugs were observed. A transverse section identified abortive sebaceous glands in hair follicles, a finding rarely observed in vertical sections. In addition, a transverse slice demonstrated that the number of total hair follicles was not significantly decreased compared with the average hair follicle density in Asians, suggesting that the pilosebaceous hypoplasia might arise from impaired maturation, not from initiation defect, during hair follicle morphogenesis. This study provides a more comprehensive pathological insight into pilosebaceous anomaly in IFAP syndrome and substantiats the usefulness of the combination of vertical and transverse sectioning approaches in the pathological examination of congenital hypotrichosis, including IFAP syndrome.
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Mégarbané H, Mégarbané A. Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome. Orphanet J Rare Dis 2011; 6:29. [PMID: 21600032 PMCID: PMC3127745 DOI: 10.1186/1750-1172-6-29] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 05/21/2011] [Indexed: 11/28/2022] Open
Abstract
The IFAP syndrome is a rare X-linked genetic disorder reported in nearly 40 patients. It is characterized by the triad of Ichthyosis Follicularis, Alopecia, and Photophobia from birth. Other features such as short stature, intellectual disability, and seizures may develop in the first few years of life. Skin histopathology is non-specific and consists of dilated hair follicles with keratin plugs extending above the surface of the skin, decreased or absent sebaceous glands, and decreased desmosomes in number and size. The disorder results from mutations in the MBTPS2 gene that impairs cholesterol homeostasis and the ability to cope with endoplasmic reticulum stress. Follicular hyperkeratosis can be treated using topical keratolytics, emollients and urea preparations. A moderate response to acitretin therapy has been noted in some patients. Intensive lubrication of the ocular surface is essential. Life expectancy in patients with IFAP syndrome can vary from death in the neonatal period to normal surviving. Cardiopulmonary complications remain the major cause of death.
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Affiliation(s)
- Hala Mégarbané
- Service de Dermatologie, Saint Georges Hospital, Beirut, Lebanon.
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15
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A novel mutation in MBTPS2 causes a broad phenotypic spectrum of ichthyosis follicularis, atrichia, and photophobia syndrome in a large Chinese family. J Am Acad Dermatol 2011; 64:716-22. [DOI: 10.1016/j.jaad.2010.02.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 02/09/2010] [Accepted: 02/14/2010] [Indexed: 11/18/2022]
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Oeffner F, Martinez F, Schaffer J, Salhi A, Monfort S, Oltra S, Neidel U, Bornholdt D, van Bon B, König A, Happle R, Grzeschik KH. Intronic mutations affecting splicing of MBTPS2 cause ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome. Exp Dermatol 2011; 20:447-9. [DOI: 10.1111/j.1600-0625.2010.01238.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Binić I, Janković A, Ljubenović M. Ichthyosis follicularis with alopecia and photophobia (IFAP): late diagnosis in 18-year-old man. Int J Dermatol 2011; 50:450-3. [PMID: 21413958 DOI: 10.1111/j.1365-4632.2010.04501.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ivana Binić
- Clinic of Dermatology and Venerology, Clinical Center Nis, Nis, Serbia.
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18
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Ding Y, Wang J, Qiao J, Mao X, Cai S. A novel mutation in MBTPS2
causes ichthyosis follicularis, alopecia and photophobia (IFAP) syndrome in a Chinese family. Br J Dermatol 2010; 163:886-9. [DOI: 10.1111/j.1365-2133.2010.09890.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fernandes NF, Janniger CK, Schwartz RA. X-linked ichthyosis: an oculocutaneous genodermatosis. J Am Acad Dermatol 2010; 62:480-5. [PMID: 20080321 DOI: 10.1016/j.jaad.2009.04.028] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 04/04/2009] [Accepted: 04/09/2009] [Indexed: 12/12/2022]
Abstract
X-linked ichthyosis (XLI) is an X-linked recessive disorder of cutaneous keratinization with possible extracutaneous manifestations. It was first described as a distinct type of ichthyosis in 1965. XLI is caused by a deficiency in steroid sulfatase activity, which results in abnormal desquamation and a retention hyperkeratosis. XLI is usually evident during the first few weeks of life as polygonal, loosely adherent translucent scales in a generalized distribution that desquamate widely. These are quickly replaced by large, dark brown, tightly adherent scales occurring primarily symmetrically on the extensor surfaces and the side of the trunk. In addition, extracutaneous manifestations such as corneal opacities, cryptorchidism, and abnormalities related to contiguous gene syndromes may be observed. Diagnosis of XLI is usually made clinically, as the histopathology is nonspecific, but confirmation may be obtained through either biochemical or genetic analysis. Treatment should focus on cutaneous hydration, lubrication, and keratolysis and includes topical moisturizers and topical retinoids.
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Affiliation(s)
- Neil F Fernandes
- Dermatology, New Jersey Medical School, Newark, New Jersey 07103, USA
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Ming A, Happle R, Grzeschik KH, Fischer G. Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome due to mutation of the gene MBTPS2 in a large Australian kindred. Pediatr Dermatol 2009; 26:427-31. [PMID: 19689518 DOI: 10.1111/j.1525-1470.2009.00946.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ichthyosis follicularis, alopecia and photophobia (IFAP) is a rare genodermatosis. Most patients have been men without significant family history. We present the largest kindred of IFAP reported to date in the medical literature clearly demonstrating X-linked inheritance. The gene defect has recently been mapped to Xp22.11-p22.13. Missense mutations of the gene, MBTPS2, which codes for an intramembrane zinc metalloprotease essential for cholesterol homeostasis and endoplasmic reticulum stress response, are associated with the IFAP phenotype in this kindred. We describe the clinical features and discuss the differential diagnosis of IFAP. Our proband has benefited from treatment with acitretin.
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Affiliation(s)
- Andrew Ming
- Department of Dermatology, Prince of Wales Hospital, Sydney, Australia.
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21
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Oeffner F, Fischer G, Happle R, König A, Betz RC, Bornholdt D, Neidel U, del Carmen Boente M, Redler S, Romero-Gomez J, Salhi A, Vera-Casaño Á, Weirich C, Grzeschik KH. IFAP syndrome is caused by deficiency in MBTPS2, an intramembrane zinc metalloprotease essential for cholesterol homeostasis and ER stress response. Am J Hum Genet 2009; 84:459-67. [PMID: 19361614 DOI: 10.1016/j.ajhg.2009.03.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 03/18/2009] [Accepted: 03/19/2009] [Indexed: 10/20/2022] Open
Abstract
Ichthyosis follicularis with atrichia and photophobia (IFAP syndrome) is a rare X-linked, oculocutaneous human disorder. Here, we assign the IFAP locus to the 5.4 Mb region between DXS989 and DXS8019 on Xp22.11-p22.13 and provide evidence that missense mutations exchanging highly conserved amino acids of membrane-bound transcription factor protease, site 2 (MBTPS2) are associated with this phenotype. MBTPS2, a membrane-embedded zinc metalloprotease, activates signaling proteins involved in sterol control of transcription and ER stress response. Wild-type MBTPS2 was able to complement the protease deficiency in Chinese hamster M19 cells as shown by induction of an SRE-regulated reporter gene in transient transfection experiments and by growth of stably transfected cells in media devoid of cholesterol and lipids. These functions were impaired in five mutations as detected in unrelated patients. The degree of diminished activity correlated with clinical severity as noted in male patients. Our findings indicate that the phenotypic expression of IFAP syndrome is quantitatively related to a reduced function of a key cellular regulatory system affecting cholesterol homeostasis and ability to cope with ER stress.
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