Hyperphenylalaninemia, Bh4-deficient, A; Hpabh4a

Description

Tetrahydrobiopterin (BH4)-deficient hyperphenylalaninemia (HPA) comprises a genetically heterogeneous group of progressive neurologic disorders caused by autosomal recessive mutations in the genes encoding enzymes involved in the synthesis or regeneration of BH4. BH4 is a cofactor for phenylalanine hydroxylase (PAH ), tyrosine hydroxylase (TH ) and tryptophan hydroxylase (TPH1 ), the latter 2 of which are involved in neurotransmitter synthesis. The BH4-deficient HPAs are characterized phenotypically by hyperphenylalaninemia, depletion of the neurotransmitters dopamine and serotonin, and progressive cognitive and motor deficits (Dudesek et al., 2001).HPABH4A, caused by mutations in the PTS gene, represents the most common cause of BH4-deficient hyperphenylalaninemia (Dudesek et al., 2001). Other forms of BH4-deficient HPA include HPABH4B (OMIM ), caused by mutation in the GCH1 gene (OMIM ), HPABH4C (OMIM ), caused by mutation in the QDPR gene (OMIM ), and HPABH4D (OMIM ), caused by mutation in the PCBD1 gene (OMIM ). Niederwieser et al. (1982) noted that about 1 to 3% of patients with hyperphenylalaninemia have one of these BH4-deficient forms. These disorders are clinically and genetically distinct from classic phenylketonuria (PKU ), caused by mutation in the PAH gene.Two additional disorders associated with BH4 deficiency and neurologic symptoms do not have overt hyperphenylalaninemia as a feature: dopa-responsive dystonia (OMIM ), caused by mutation in the SPR gene (OMIM ), and autosomal dominant dopa-responsive dystonia (DYT5 ), caused by mutation in the GCH1 gene. Patients with these disorders may develop hyperphenylalaninemia when stressed.

Clinical Features

Top most frequent phenotypes and symptoms related to Hyperphenylalaninemia, Bh4-deficient, A; Hpabh4a

  • Seizures
  • Global developmental delay
  • Generalized hypotonia
  • Microcephaly
  • Ataxia
  • Motor delay
  • Hyperreflexia
  • Tremor
  • Gait disturbance
  • Dysphagia

And another 21 symptoms. If you need more information about this disease we can help you.

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Incidence and onset information

— Currently we don't have prevalence information about this disease (Not enough data available about incidence and published cases.)
No data available about the known clinical features onset.

Alternative names

Hyperphenylalaninemia, Bh4-deficient, A; Hpabh4a Is also known as hyperphenylalaninemia, tetrahydrobiopterin-deficient, due to pts deficiency, 6-pyruvoyl-tetrahydropterin synthase deficiency, pts deficiency.

Researches and researchers

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Hyperphenylalaninemia, Bh4-deficient, A; Hpabh4a Recommended genes panels

Panel Name, Specifity and genes Tested/covered
MitoMetĀ®Plus aCGH Analysis.

By Baylor Miraca Genetics Laboratories (United States).

RGS9, RHO, GRK1, RLBP1, RNASEL, BCS1L, RP1, RP2, RP9, RPE65, RPGR, RPL35A, MRPL3, RPS14, RS1, SAG, SARDH, SCO2, SCP2, SDHB , (...)

View the complete list with 612 more genes
Specificity
1 %
Genes
100 %
GeneAware Complete Panel Version 2 (Female).

By Baylor Miraca Genetics Laboratories (United States).

RMRP, BCS1L, SACS, BLM, SGCA, SGCB, SGCG, SGSH, SLC12A6, SLC17A5, SLC22A5, SLC25A13, SLC25A15, SLC26A2, SLC35A3, SLC7A7, SMN1, SMPD1, BTD, BTK , (...)

View the complete list with 139 more genes
Specificity
1 %
Genes
100 %
GeneAware Complete Panel Version 2 (Male).

By Baylor Miraca Genetics Laboratories (United States).

RMRP, BCS1L, SACS, BLM, SGCA, SGCB, SGCG, SGSH, SLC12A6, SLC17A5, SLC22A5, SLC25A13, SLC25A15, SLC26A2, SLC35A3, SLC7A7, SMN1, SMPD1, BTD, TGM1 , (...)

View the complete list with 129 more genes
Specificity
1 %
Genes
100 %
Dystonia.

By Knight Diagnostic Laboratories - Molecular Diagnostic Center Oregon Health & Science University (United States).

SCP2, SGCE, SLC20A2, SLC2A1, SLC6A3, SPR, SUCLA2, SUOX, TAF1, TH, TIMM8A, TREX1, MCOLN1, FBXO7, CACNA1A, NPC2, PINK1, PANK2, SAMHD1, APTX , (...)

View the complete list with 57 more genes
Specificity
2 %
Genes
100 %
Epilepsy/Seizure.

By Knight Diagnostic Laboratories - Molecular Diagnostic Center Oregon Health & Science University (United States).

SCN1A, SCN1B, SCN2A, SCN8A, SCN9A, SLC2A1, SLC6A8, SLC9A6, BTD, SPTAN1, CDKL5, STXBP1, SYN1, TSC1, TSC2, UBE3A, CNTNAP2, CACNA1A, CACNB4, ARHGEF9 , (...)

View the complete list with 78 more genes
Specificity
2 %
Genes
100 %
Infantile Epilepsy.

By Knight Diagnostic Laboratories - Molecular Diagnostic Center Oregon Health & Science University (United States).

SCN1A, SCN1B, SCN2A, SCN8A, SLC2A1, SLC6A8, SLC9A6, BTD, SPTAN1, CDKL5, STXBP1, TCF4, TSC1, TSC2, UBE3A, CNTNAP2, ZEB2, LIAS, ARX, MAGI2 , (...)

View the complete list with 40 more genes
Specificity
2 %
Genes
100 %
Movement Disorders Panel.

By Knight Diagnostic Laboratories - Molecular Diagnostic Center Oregon Health & Science University (United States).

SCP2, SGCE, SLC20A2, SLC2A1, SLC6A3, SNCA, SPR, SQSTM1, SUCLA2, SUOX, TAF1, TH, TIMM8A, TREX1, MCOLN1, VPS35, FBXO7, CACNA1A, NPC2, PINK1 , (...)

View the complete list with 72 more genes
Specificity
2 %
Genes
100 %
6-Pyruvoyltetrahydropterin Synthase Deficiency.

By Medical Genetics Laboratory, Kennedy Center Juliane Marie Center, Rigshospitalet (Denmark).

PTS
Specificity
100 %
Genes
100 %

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Sources and references

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