Lamellar Ichthyosis Type 1

Most neonates with autosomal recessive congenital ichthyosis present as collodion babies. Collodion babies are born with a taut, shiny, translucent or opaque membrane that encases the entire body and lasts for days to weeks. Affected individuals with severe involvement can have ectropion, eclabium, scarring alopecia involving the scalp and eyebrows, and palmar and plantar hyperkeratosis. After the collodion membrane has been shed, the clinical presentation and severity of congenital recessive ichthyosis may greatly vary between individuals. Congenital recessive ichthyosis encompass a wide spectrum, extending from severe ‘classic’ lamellar ichthyosis with dark brown, plate-like scale without erythroderma to congenital ichthyosiform erythroderma with finer, whitish scale and underlying generalized redness of the skin. The severity of congenital recessive ichthyosis ranges from severe (‘classic’ lamellar ichthyosis) to mild (mild lamellar ichthyosis, mild non-bullous congenital ichthyosiform erythroderma) or almost complete resolution of the skin disorder (so-called ‘self-healing collodion baby’). Although these phenotypes are now recognized to fall on a continuum, the phenotypic classification can be clinically useful for clarifying prognosis and management for individuals and, to some extent, to choose which genes to analyze. A skin biopsy is not necessary to establish the diagnosis of autosomal recessive congenital ichthyosis, and is usually not helpful in differentiating among the different clinical disorders along the spectrum. However, a skin biopsy is useful to differentiate the nonbullous from the bullous forms of ichthyosis. Thus, if blistering is present, histopathological evaluation can be a useful diagnostic tool. Approximately 1 in 225 individuals is a carrier for lamellar ichthyosis/NCIE1 due to mutation in the TGM1 gene, and the disorder has been described in all races and ethnicities.

Tests Available

Forms and Documents

Test Details

TGM1
  • Confirmation of a clinical diagnosis
  • Carrier testing in unaffected family members
  • Prenatal diagnosis
  • Capillary Sequencing

Ordering

125
3 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Dried Blood Spots|Buccal Swabs

Billing

81479x1
Yes
Yes
  • 757.1 Ichthyosis congenita, Congenital ichthyosis, Harlequin fetus, Ichthyosiform erythroderma
  • 757.39 Other Accessory skin tags, congenital, Congenital scar, Epidermolysis bullosa, Keratoderma (congenital)
* For price inquiries please email zebras@genedx.com

References

  1. Huber M, et al., Mutations of keratinocyte transglutaminase in lamellar ichthyosis. Science 267:525-8 (1995)
  2. Russell LJ, et al., Mutations in the gene for transglutaminase 1 in autosomal recessive lamellar ichthyosis. Nat Genet 9:279-83 (1995)
  3. Shevchenko YO, et al., Splice-site mutation in TGM1 in congenital recessive ichthyosis in American families: molecular, genetic, genealogic, and clinical studies. Hum Genet 106:492-9 (2000).

Forms and Documents

Test Details

ABCA12, ABHD5, AGPS, ALDH3A2, ALOX12B, ALOXE3, AP1S1, ARSE, CASP14, CERS3, CLDN1, CYP4F22, EBP, ELOVL4, FLG, GJB2 (Cx26), GJB3 (Cx31), GJB4 (Cx30.3), GJB6 (Cx30), KRT1, KRT10, KRT2, KRT9, LIPN, LOR, NIPAL4(Ichthyin), PEX7, PHGDH, PHYH, PNPLA1, PNPLA2, POMP, PSAT1, SDR9C7, SLC27A4, SNAP29, SPINK5, ST14, STS, TGM1, TGM5, VPS33B, ZMPSTE24
  • Identification of the specific molecular basis of congential ichthyosis or related skin disorders
  • Genetic counseling and recurrence risk assessment
  • Option for prenatal testing in future pregnancies

As needed, based on the referring diagnosis and coverage achieved by the XomeDxSlice-Ichthyosis for a given patient, critical exons with a high yield of mutations will be filled-in by dideoxy sequencing. For any autosomal recessive gene, if one definitive mutation is found by XomeDxSlice sequencing, AND the gene fits the type of ichthyosis reported by the referring physician, capillary sequencing will be used to fill in sequence for exons that are not sufficiently covered (>10X) to find the second mutation. If no second mutation is found by sequencing, deletion/duplication analysis of that gene can be performed at no additional cost can be performed at no additional cost.

Patient samples sent for XomeDxSlice will not be evaluated for secondary findings and therefore will not receive secondary findings as part of their result.\\\"

  • Next-Gen Sequencing

Ordering

708
6 weeks
2-5 mL Blood - Lavender Top Tube
Oral Rinse (30-40 mL)|Dried Blood Spots|Buccal Swabs

Billing

81252x1, 81254x1, 81479x11
Yes
Yes
* For price inquiries please email zebras@genedx.com