PIBIDS Syndrome
Photosensitivity, Ichthyosis, Brittle hair, Impaired intelligence, Decreased fertility, Short stature. Part of the trichothiodystrophy spectrum — a DNA repair disorder.
Mutations in ERCC2 (XPD) or ERCC3 (XPB) impair nucleotide excision repair — the cell's ability to fix DNA damaged by UV radiation and other causes. This affects multiple tissues.
Severe sun sensitivity — burning with minimal exposure. UNLIKE xeroderma pigmentosum (same repair pathway), PIBIDS/TTD does NOT significantly increase skin cancer risk.
Hallmark feature: hair has very low sulphur content, visible as alternating light/dark bands under polarised light microscopy. Hair breaks easily and may be sparse.
Varying degrees of intellectual disability, ataxia (balance difficulties), microcephaly. MRI often shows dysmyelination. Severity varies widely between individuals.
Daily Management
- Emollient-first approach — Diprobase or Epaderm twice daily as the foundation
- Keratolytic cream — Urea 10–20% for scaled areas (arms, legs, trunk)
- Warm baths only — Never hot. Bath oil (Oilatum) to reduce drying. Apply emollient immediately after.
- Fragrance-free products throughout — Photosensitised skin is also often more reactive to fragrances
- Protective clothing — UPF50+ clothing for outdoor activities; long sleeves even in warm weather
- SPF 50+ broad-spectrum sunscreen — Every morning, year-round, rain or shine. Reapply every 2 hours outdoors.
- Mineral sunscreens preferred — Zinc oxide or titanium dioxide formulations. Better for sensitive skin and more photostable.
- UV-blocking window film — For car windows and home windows facing sun. Reduces indoor UV exposure significantly.
- Broad-brimmed hat — Minimum 7.5cm brim for effective face protection. Required for any outdoor activity.
- UV-protective clothing — UPF50+ rated garments. Some brands: Coolibar, Sun Precautions.
- School plan — Written sun protection plan for school. Legal requirement to make reasonable accommodations.
- Avoid 11am–3pm outdoors — Highest UV index periods. Plan activities accordingly.
Neurological involvement varies significantly in PIBIDS. Coordinate with a paediatric neurologist or neurologist experienced in metabolic conditions:
- Special educational needs (SEN) assessment — Most children with PIBIDS qualify for an Education, Health and Care (EHC) plan
- Physiotherapy for ataxia — Balance exercises, fall prevention, mobility aids if needed
- Speech and language therapy — For communication difficulties
- Occupational therapy — For fine motor difficulties, daily living aids
- MRI monitoring — Neurologist will advise on frequency of monitoring
- Epilepsy monitoring — Seizures can occur; ensure emergency medication plan if applicable
Brittle hair is a hallmark of TTD/PIBIDS. It requires very gentle handling:
- Gentle, fragrance-free shampoo (baby shampoo formula)
- No heat styling, bleaching, or chemical treatment of any kind
- Wide-tooth comb only, very gently on wet hair
- Hat or head covering outdoors — provides sun and physical protection
- Hair does not significantly improve with skin treatments — it reflects the underlying DNA repair deficiency
- Diagnosis can be confirmed by trichoscopy (polarised light microscopy) showing tiger-tail banding pattern
Medications
| Treatment | Purpose | Evidence | Notes |
|---|---|---|---|
| Mineral sunscreen SPF50+ | UV protection (non-negotiable) | Essential | Year-round. No alternatives. |
| Emollients (Epaderm, Diprobase) | Skin barrier — ichthyosis management | Established | Twice daily. Cornerstone of skin care. |
| Urea 10–20% cream | Keratolytic for scaling | Established | For scaled areas on body |
| Acitretin | Skin scaling (severe cases) | Limited TTD data | May help skin component; not studied specifically in PIBIDS |
| Vitamin D supplementation | Compensate for sun avoidance | Recommended | Sun avoidance = vitamin D deficiency risk. Supplement with GP guidance. |
Red Flags
- Severe sunburn — may require emergency treatment
- New or worsening neurological symptoms (seizures, sudden loss of skill, falls)
- Infection on photosensitised skin
- Sudden deterioration in hearing or vision